stream pushing ok without access permission of /dev/video0
[rtmpclient.git] / app / src / main / jni / libusb / libusb / os / windows_usb.c
diff --git a/app/src/main/jni/libusb/libusb/os/windows_usb.c b/app/src/main/jni/libusb/libusb/os/windows_usb.c
new file mode 100644 (file)
index 0000000..e130bc9
--- /dev/null
@@ -0,0 +1,4424 @@
+/*
+ * windows backend for libusb 1.0
+ * Copyright © 2009-2012 Pete Batard <pete@akeo.ie>
+ * With contributions from Michael Plante, Orin Eman et al.
+ * Parts of this code adapted from libusb-win32-v1 by Stephan Meyer
+ * HID Reports IOCTLs inspired from HIDAPI by Alan Ott, Signal 11 Software
+ * Hash table functions adapted from glibc, by Ulrich Drepper et al.
+ * Major code testing contribution by Xiaofan Chen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+#include <windows.h>
+#include <setupapi.h>
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <process.h>
+#include <stdio.h>
+#include <inttypes.h>
+#include <objbase.h>
+#include <winioctl.h>
+
+#include "libusbi.h"
+#include "poll_windows.h"
+#include "windows_usb.h"
+
+// The 2 macros below are used in conjunction with safe loops.
+#define LOOP_CHECK(fcall) { r=fcall; if (r != LIBUSB_SUCCESS) continue; }
+#define LOOP_BREAK(err) { r=err; continue; }
+
+// Helper prototypes
+static int windows_get_active_config_descriptor(struct libusb_device *dev, unsigned char *buffer, size_t len, int *host_endian);
+static int windows_clock_gettime(int clk_id, struct timespec *tp);
+unsigned __stdcall windows_clock_gettime_threaded(void* param);
+// Common calls
+static int common_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+
+// WinUSB-like API prototypes
+static int winusbx_init(int sub_api, struct libusb_context *ctx);
+static int winusbx_exit(int sub_api);
+static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle);
+static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle);
+static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
+static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
+static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
+static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer);
+static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
+static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
+// HID API prototypes
+static int hid_init(int sub_api, struct libusb_context *ctx);
+static int hid_exit(int sub_api);
+static int hid_open(int sub_api, struct libusb_device_handle *dev_handle);
+static void hid_close(int sub_api, struct libusb_device_handle *dev_handle);
+static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
+static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
+static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
+static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
+static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
+// Composite API prototypes
+static int composite_init(int sub_api, struct libusb_context *ctx);
+static int composite_exit(int sub_api);
+static int composite_open(int sub_api, struct libusb_device_handle *dev_handle);
+static void composite_close(int sub_api, struct libusb_device_handle *dev_handle);
+static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
+static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
+static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer);
+static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
+static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
+static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer);
+static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
+static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
+
+
+// Global variables
+uint64_t hires_frequency, hires_ticks_to_ps;
+const uint64_t epoch_time = UINT64_C(116444736000000000);      // 1970.01.01 00:00:000 in MS Filetime
+enum windows_version windows_version = WINDOWS_UNSUPPORTED;
+// Concurrency
+static int concurrent_usage = -1;
+usbi_mutex_t autoclaim_lock;
+// Timer thread
+// NB: index 0 is for monotonic and 1 is for the thread exit event
+HANDLE timer_thread = NULL;
+HANDLE timer_mutex = NULL;
+struct timespec timer_tp;
+volatile LONG request_count[2] = {0, 1};       // last one must be > 0
+HANDLE timer_request[2] = { NULL, NULL };
+HANDLE timer_response = NULL;
+// API globals
+#define CHECK_WINUSBX_AVAILABLE(sub_api) do { if (sub_api == SUB_API_NOTSET) sub_api = priv->sub_api; \
+       if (!WinUSBX[sub_api].initialized) return LIBUSB_ERROR_ACCESS; } while(0)
+static struct winusb_interface WinUSBX[SUB_API_MAX];
+const char* sub_api_name[SUB_API_MAX] = WINUSBX_DRV_NAMES;
+bool api_hid_available = false;
+#define CHECK_HID_AVAILABLE do { if (!api_hid_available) return LIBUSB_ERROR_ACCESS; } while (0)
+
+static inline BOOLEAN guid_eq(const GUID *guid1, const GUID *guid2) {
+       if ((guid1 != NULL) && (guid2 != NULL)) {
+               return (memcmp(guid1, guid2, sizeof(GUID)) == 0);
+       }
+       return false;
+}
+
+#if defined(ENABLE_LOGGING)
+static char* guid_to_string(const GUID* guid)
+{
+       static char guid_string[MAX_GUID_STRING_LENGTH];
+
+       if (guid == NULL) return NULL;
+       sprintf(guid_string, "{%08X-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X}",
+               (unsigned int)guid->Data1, guid->Data2, guid->Data3,
+               guid->Data4[0], guid->Data4[1], guid->Data4[2], guid->Data4[3],
+               guid->Data4[4], guid->Data4[5], guid->Data4[6], guid->Data4[7]);
+       return guid_string;
+}
+#endif
+
+/*
+ * Converts a windows error to human readable string
+ * uses retval as errorcode, or, if 0, use GetLastError()
+ */
+#if defined(ENABLE_LOGGING)
+static char *windows_error_str(uint32_t retval)
+{
+static char err_string[ERR_BUFFER_SIZE];
+
+       DWORD size;
+       ssize_t i;
+       uint32_t error_code, format_error;
+
+       error_code = retval?retval:GetLastError();
+
+       safe_sprintf(err_string, ERR_BUFFER_SIZE, "[%u] ", error_code);
+
+       // Translate codes returned by SetupAPI. The ones we are dealing with are either
+       // in 0x0000xxxx or 0xE000xxxx and can be distinguished from standard error codes.
+       // See http://msdn.microsoft.com/en-us/library/windows/hardware/ff545011.aspx
+       switch (error_code & 0xE0000000) {
+       case 0:
+               error_code = HRESULT_FROM_WIN32(error_code);    // Still leaves ERROR_SUCCESS unmodified
+               break;
+       case 0xE0000000:
+               error_code =  0x80000000 | (FACILITY_SETUPAPI << 16) | (error_code & 0x0000FFFF);
+               break;
+       default:
+               break;
+       }
+
+       size = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, NULL, error_code,
+               MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), &err_string[safe_strlen(err_string)],
+               ERR_BUFFER_SIZE - (DWORD)safe_strlen(err_string), NULL);
+       if (size == 0) {
+               format_error = GetLastError();
+               if (format_error)
+                       safe_sprintf(err_string, ERR_BUFFER_SIZE,
+                               "Windows error code %u (FormatMessage error code %u)", error_code, format_error);
+               else
+                       safe_sprintf(err_string, ERR_BUFFER_SIZE, "Unknown error code %u", error_code);
+       } else {
+               // Remove CR/LF terminators
+               for (i=safe_strlen(err_string)-1; (i>=0) && ((err_string[i]==0x0A) || (err_string[i]==0x0D)); i--) {
+                       err_string[i] = 0;
+               }
+       }
+       return err_string;
+}
+#endif
+
+/*
+ * Sanitize Microsoft's paths: convert to uppercase, add prefix and fix backslashes.
+ * Return an allocated sanitized string or NULL on error.
+ */
+static char* sanitize_path(const char* path)
+{
+       const char root_prefix[] = "\\\\.\\";
+       size_t j, size, root_size;
+       char* ret_path = NULL;
+       size_t add_root = 0;
+
+       if (path == NULL)
+               return NULL;
+
+       size = safe_strlen(path)+1;
+       root_size = sizeof(root_prefix)-1;
+
+       // Microsoft indiscriminatly uses '\\?\', '\\.\', '##?#" or "##.#" for root prefixes.
+       if (!((size > 3) && (((path[0] == '\\') && (path[1] == '\\') && (path[3] == '\\')) ||
+               ((path[0] == '#') && (path[1] == '#') && (path[3] == '#'))))) {
+               add_root = root_size;
+               size += add_root;
+       }
+
+       if ((ret_path = (char*) calloc(size, 1)) == NULL)
+               return NULL;
+
+       safe_strcpy(&ret_path[add_root], size-add_root, path);
+
+       // Ensure consistancy with root prefix
+       for (j=0; j<root_size; j++)
+               ret_path[j] = root_prefix[j];
+
+       // Same goes for '\' and '#' after the root prefix. Ensure '#' is used
+       for(j=root_size; j<size; j++) {
+               ret_path[j] = (char)toupper((int)ret_path[j]);  // Fix case too
+               if (ret_path[j] == '\\')
+                       ret_path[j] = '#';
+       }
+
+       return ret_path;
+}
+
+/*
+ * Cfgmgr32, OLE32 and SetupAPI DLL functions
+ */
+static int init_dlls(void)
+{
+       DLL_LOAD(Cfgmgr32.dll, CM_Get_Parent, TRUE);
+       DLL_LOAD(Cfgmgr32.dll, CM_Get_Child, TRUE);
+       DLL_LOAD(Cfgmgr32.dll, CM_Get_Sibling, TRUE);
+       DLL_LOAD(Cfgmgr32.dll, CM_Get_Device_IDA, TRUE);
+       // Prefixed to avoid conflict with header files
+       DLL_LOAD_PREFIXED(OLE32.dll, p, CLSIDFromString, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiGetClassDevsA, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiEnumDeviceInfo, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiEnumDeviceInterfaces, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiGetDeviceInterfaceDetailA, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiDestroyDeviceInfoList, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiOpenDevRegKey, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiGetDeviceRegistryPropertyA, TRUE);
+       DLL_LOAD_PREFIXED(SetupAPI.dll, p, SetupDiOpenDeviceInterfaceRegKey, TRUE);
+       DLL_LOAD_PREFIXED(AdvAPI32.dll, p, RegQueryValueExW, TRUE);
+       DLL_LOAD_PREFIXED(AdvAPI32.dll, p, RegCloseKey, TRUE);
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * enumerate interfaces for the whole USB class
+ *
+ * Parameters:
+ * dev_info: a pointer to a dev_info list
+ * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
+ * usb_class: the generic USB class for which to retrieve interface details
+ * index: zero based index of the interface in the device info list
+ *
+ * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
+ * structure returned and call this function repeatedly using the same guid (with an
+ * incremented index starting at zero) until all interfaces have been returned.
+ */
+static bool get_devinfo_data(struct libusb_context *ctx,
+       HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const char* usb_class, unsigned _index)
+{
+       if (_index <= 0) {
+               *dev_info = pSetupDiGetClassDevsA(NULL, usb_class, NULL, DIGCF_PRESENT|DIGCF_ALLCLASSES);
+               if (*dev_info == INVALID_HANDLE_VALUE) {
+                       return false;
+               }
+       }
+
+       dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
+       if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
+               if (GetLastError() != ERROR_NO_MORE_ITEMS) {
+                       usbi_err(ctx, "Could not obtain device info data for index %u: %s",
+                               _index, windows_error_str(0));
+               }
+               pSetupDiDestroyDeviceInfoList(*dev_info);
+               *dev_info = INVALID_HANDLE_VALUE;
+               return false;
+       }
+       return true;
+}
+
+/*
+ * enumerate interfaces for a specific GUID
+ *
+ * Parameters:
+ * dev_info: a pointer to a dev_info list
+ * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
+ * guid: the GUID for which to retrieve interface details
+ * index: zero based index of the interface in the device info list
+ *
+ * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
+ * structure returned and call this function repeatedly using the same guid (with an
+ * incremented index starting at zero) until all interfaces have been returned.
+ */
+static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details(struct libusb_context *ctx,
+       HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID* guid, unsigned _index)
+{
+       SP_DEVICE_INTERFACE_DATA dev_interface_data;
+       SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
+       DWORD size;
+
+       if (_index <= 0) {
+               *dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);
+       }
+
+       if (dev_info_data != NULL) {
+               dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
+               if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
+                       if (GetLastError() != ERROR_NO_MORE_ITEMS) {
+                               usbi_err(ctx, "Could not obtain device info data for index %u: %s",
+                                       _index, windows_error_str(0));
+                       }
+                       pSetupDiDestroyDeviceInfoList(*dev_info);
+                       *dev_info = INVALID_HANDLE_VALUE;
+                       return NULL;
+               }
+       }
+
+       dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
+       if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
+               if (GetLastError() != ERROR_NO_MORE_ITEMS) {
+                       usbi_err(ctx, "Could not obtain interface data for index %u: %s",
+                               _index, windows_error_str(0));
+               }
+               pSetupDiDestroyDeviceInfoList(*dev_info);
+               *dev_info = INVALID_HANDLE_VALUE;
+               return NULL;
+       }
+
+       // Read interface data (dummy + actual) to access the device path
+       if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
+               // The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
+               if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+                       usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
+                               _index, windows_error_str(0));
+                       goto err_exit;
+               }
+       } else {
+               usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
+               goto err_exit;
+       }
+
+       if ((dev_interface_details = (SP_DEVICE_INTERFACE_DETAIL_DATA_A*) calloc(size, 1)) == NULL) {
+               usbi_err(ctx, "could not allocate interface data for index %u.", _index);
+               goto err_exit;
+       }
+
+       dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
+       if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data,
+               dev_interface_details, size, &size, NULL)) {
+               usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
+                       _index, windows_error_str(0));
+       }
+
+       return dev_interface_details;
+
+err_exit:
+       pSetupDiDestroyDeviceInfoList(*dev_info);
+       *dev_info = INVALID_HANDLE_VALUE;
+       return NULL;
+}
+
+/* For libusb0 filter */
+static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details_filter(struct libusb_context *ctx,
+       HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID* guid, unsigned _index, char* filter_path){
+       SP_DEVICE_INTERFACE_DATA dev_interface_data;
+       SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
+       DWORD size;
+       if (_index <= 0) {
+               *dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);
+       }
+       if (dev_info_data != NULL) {
+               dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
+               if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
+                       if (GetLastError() != ERROR_NO_MORE_ITEMS) {
+                               usbi_err(ctx, "Could not obtain device info data for index %u: %s",
+                                       _index, windows_error_str(0));
+                       }
+                       pSetupDiDestroyDeviceInfoList(*dev_info);
+                       *dev_info = INVALID_HANDLE_VALUE;
+                       return NULL;
+               }
+       }
+       dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
+       if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
+               if (GetLastError() != ERROR_NO_MORE_ITEMS) {
+                       usbi_err(ctx, "Could not obtain interface data for index %u: %s",
+                               _index, windows_error_str(0));
+               }
+               pSetupDiDestroyDeviceInfoList(*dev_info);
+               *dev_info = INVALID_HANDLE_VALUE;
+               return NULL;
+       }
+       // Read interface data (dummy + actual) to access the device path
+       if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
+               // The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
+               if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
+                       usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
+                               _index, windows_error_str(0));
+                       goto err_exit;
+               }
+       } else {
+               usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
+               goto err_exit;
+       }
+       if ((dev_interface_details = malloc(size)) == NULL) {
+               usbi_err(ctx, "could not allocate interface data for index %u.", _index);
+               goto err_exit;
+       }
+       dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
+       if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data,
+               dev_interface_details, size, &size, NULL)) {
+               usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
+                       _index, windows_error_str(0));
+       }
+       // [trobinso] lookup the libusb0 symbolic index.
+       if (dev_interface_details) {
+               HKEY hkey_device_interface=pSetupDiOpenDeviceInterfaceRegKey(*dev_info,&dev_interface_data,0,KEY_READ);
+               if (hkey_device_interface != INVALID_HANDLE_VALUE) {
+                       DWORD libusb0_symboliclink_index=0;
+                       DWORD value_length=sizeof(DWORD);
+                       DWORD value_type=0;
+                       LONG status;
+                       status = pRegQueryValueExW(hkey_device_interface, L"LUsb0", NULL, &value_type,
+                               (LPBYTE) &libusb0_symboliclink_index, &value_length);
+                       if (status == ERROR_SUCCESS) {
+                               if (libusb0_symboliclink_index < 256) {
+                                       // libusb0.sys is connected to this device instance.
+                                       // If the the device interface guid is {F9F3FF14-AE21-48A0-8A25-8011A7A931D9} then it's a filter.
+                                       safe_sprintf(filter_path, sizeof("\\\\.\\libusb0-0000"), "\\\\.\\libusb0-%04d", libusb0_symboliclink_index);
+                                       usbi_dbg("assigned libusb0 symbolic link %s", filter_path);
+                               } else {
+                                       // libusb0.sys was connected to this device instance at one time; but not anymore.
+                               }
+                       }
+                       pRegCloseKey(hkey_device_interface);
+               }
+       }
+       return dev_interface_details;
+err_exit:
+       pSetupDiDestroyDeviceInfoList(*dev_info);
+       *dev_info = INVALID_HANDLE_VALUE;
+       return NULL;}
+
+/* Hash table functions - modified From glibc 2.3.2:
+   [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986
+   [Knuth]            The Art of Computer Programming, part 3 (6.4)  */
+typedef struct htab_entry {
+       unsigned long used;
+       char* str;
+} htab_entry;
+htab_entry* htab_table = NULL;
+usbi_mutex_t htab_write_mutex = NULL;
+unsigned long htab_size, htab_filled;
+
+/* For the used double hash method the table size has to be a prime. To
+   correct the user given table size we need a prime test.  This trivial
+   algorithm is adequate because the code is called only during init and
+   the number is likely to be small  */
+static int isprime(unsigned long number)
+{
+       // no even number will be passed
+       unsigned int divider = 3;
+
+       while((divider * divider < number) && (number % divider != 0))
+               divider += 2;
+
+       return (number % divider != 0);
+}
+
+/* Before using the hash table we must allocate memory for it.
+   We allocate one element more as the found prime number says.
+   This is done for more effective indexing as explained in the
+   comment for the hash function.  */
+static int htab_create(struct libusb_context *ctx, unsigned long nel)
+{
+       if (htab_table != NULL) {
+               usbi_err(ctx, "hash table already allocated");
+       }
+
+       // Create a mutex
+       usbi_mutex_init(&htab_write_mutex, NULL);
+
+       // Change nel to the first prime number not smaller as nel.
+       nel |= 1;
+       while(!isprime(nel))
+               nel += 2;
+
+       htab_size = nel;
+       usbi_dbg("using %d entries hash table", nel);
+       htab_filled = 0;
+
+       // allocate memory and zero out.
+       htab_table = (htab_entry*) calloc(htab_size + 1, sizeof(htab_entry));
+       if (htab_table == NULL) {
+               usbi_err(ctx, "could not allocate space for hash table");
+               return 0;
+       }
+
+       return 1;
+}
+
+/* After using the hash table it has to be destroyed.  */
+static void htab_destroy(void)
+{
+       size_t i;
+       if (htab_table == NULL) {
+               return;
+       }
+
+       for (i=0; i<htab_size; i++) {
+               if (htab_table[i].used) {
+                       safe_free(htab_table[i].str);
+               }
+       }
+       usbi_mutex_destroy(&htab_write_mutex);
+       safe_free(htab_table);
+}
+
+/* This is the search function. It uses double hashing with open addressing.
+   We use an trick to speed up the lookup. The table is created with one
+   more element available. This enables us to use the index zero special.
+   This index will never be used because we store the first hash index in
+   the field used where zero means not used. Every other value means used.
+   The used field can be used as a first fast comparison for equality of
+   the stored and the parameter value. This helps to prevent unnecessary
+   expensive calls of strcmp.  */
+static unsigned long htab_hash(char* str)
+{
+       unsigned long hval, hval2;
+       unsigned long idx;
+       unsigned long r = 5381;
+       int c;
+       char* sz = str;
+
+       if (str == NULL)
+               return 0;
+
+       // Compute main hash value (algorithm suggested by Nokia)
+       while ((c = *sz++) != 0)
+               r = ((r << 5) + r) + c;
+       if (r == 0)
+               ++r;
+
+       // compute table hash: simply take the modulus
+       hval = r % htab_size;
+       if (hval == 0)
+               ++hval;
+
+       // Try the first index
+       idx = hval;
+
+       if (htab_table[idx].used) {
+               if ( (htab_table[idx].used == hval)
+                 && (safe_strcmp(str, htab_table[idx].str) == 0) ) {
+                       // existing hash
+                       return idx;
+               }
+               usbi_dbg("hash collision ('%s' vs '%s')", str, htab_table[idx].str);
+
+               // Second hash function, as suggested in [Knuth]
+               hval2 = 1 + hval % (htab_size - 2);
+
+               do {
+                       // Because size is prime this guarantees to step through all available indexes
+                       if (idx <= hval2) {
+                               idx = htab_size + idx - hval2;
+                       } else {
+                               idx -= hval2;
+                       }
+
+                       // If we visited all entries leave the loop unsuccessfully
+                       if (idx == hval) {
+                               break;
+                       }
+
+                       // If entry is found use it.
+                       if ( (htab_table[idx].used == hval)
+                         && (safe_strcmp(str, htab_table[idx].str) == 0) ) {
+                               return idx;
+                       }
+               }
+               while (htab_table[idx].used);
+       }
+
+       // Not found => New entry
+
+       // If the table is full return an error
+       if (htab_filled >= htab_size) {
+               usbi_err(NULL, "hash table is full (%d entries)", htab_size);
+               return 0;
+       }
+
+       // Concurrent threads might be storing the same entry at the same time
+       // (eg. "simultaneous" enums from different threads) => use a mutex
+       usbi_mutex_lock(&htab_write_mutex);
+       // Just free any previously allocated string (which should be the same as
+       // new one). The possibility of concurrent threads storing a collision
+       // string (same hash, different string) at the same time is extremely low
+       safe_free(htab_table[idx].str);
+       htab_table[idx].used = hval;
+       htab_table[idx].str = (char*) malloc(safe_strlen(str)+1);
+       if (htab_table[idx].str == NULL) {
+               usbi_err(NULL, "could not duplicate string for hash table");
+               usbi_mutex_unlock(&htab_write_mutex);
+               return 0;
+       }
+       memcpy(htab_table[idx].str, str, safe_strlen(str)+1);
+       ++htab_filled;
+       usbi_mutex_unlock(&htab_write_mutex);
+
+       return idx;
+}
+
+/*
+ * Returns the session ID of a device's nth level ancestor
+ * If there's no device at the nth level, return 0
+ */
+static unsigned long get_ancestor_session_id(DWORD devinst, unsigned level)
+{
+       DWORD parent_devinst;
+       unsigned long session_id = 0;
+       char* sanitized_path = NULL;
+       char path[MAX_PATH_LENGTH];
+       unsigned i;
+
+       if (level < 1) return 0;
+       for (i = 0; i<level; i++) {
+               if (CM_Get_Parent(&parent_devinst, devinst, 0) != CR_SUCCESS) {
+                       return 0;
+               }
+               devinst = parent_devinst;
+       }
+       if (CM_Get_Device_IDA(devinst, path, MAX_PATH_LENGTH, 0) != CR_SUCCESS) {
+               return 0;
+       }
+       // TODO: (post hotplug): try without sanitizing
+       sanitized_path = sanitize_path(path);
+       if (sanitized_path == NULL) {
+               return 0;
+       }
+       session_id = htab_hash(sanitized_path);
+       safe_free(sanitized_path);
+       return session_id;
+}
+
+/*
+ * Populate the endpoints addresses of the device_priv interface helper structs
+ */
+static int windows_assign_endpoints(struct libusb_device_handle *dev_handle, int iface, int altsetting)
+{
+       int i, r;
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct libusb_config_descriptor *conf_desc;
+       const struct libusb_interface_descriptor *if_desc;
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+
+       r = libusb_get_config_descriptor(dev_handle->dev, 0, &conf_desc);
+       if (r != LIBUSB_SUCCESS) {
+               usbi_warn(ctx, "could not read config descriptor: error %d", r);
+               return r;
+       }
+
+       if_desc = &conf_desc->interface[iface].altsetting[altsetting];
+       safe_free(priv->usb_interface[iface].endpoint);
+
+       if (if_desc->bNumEndpoints == 0) {
+               usbi_dbg("no endpoints found for interface %d", iface);
+               return LIBUSB_SUCCESS;
+       }
+
+       priv->usb_interface[iface].endpoint = (uint8_t*) malloc(if_desc->bNumEndpoints);
+       if (priv->usb_interface[iface].endpoint == NULL) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       priv->usb_interface[iface].nb_endpoints = if_desc->bNumEndpoints;
+       for (i=0; i<if_desc->bNumEndpoints; i++) {
+               priv->usb_interface[iface].endpoint[i] = if_desc->endpoint[i].bEndpointAddress;
+               usbi_dbg("(re)assigned endpoint %02X to interface %d", priv->usb_interface[iface].endpoint[i], iface);
+       }
+       libusb_free_config_descriptor(conf_desc);
+
+       // Extra init may be required to configure endpoints
+       return priv->apib->configure_endpoints(SUB_API_NOTSET, dev_handle, iface);
+}
+
+// Lookup for a match in the list of API driver names
+// return -1 if not found, driver match number otherwise
+static int get_sub_api(char* driver, int api){
+       int i;
+       const char sep_str[2] = {LIST_SEPARATOR, 0};
+       char *tok, *tmp_str;
+       size_t len = safe_strlen(driver);
+
+       if (len == 0) return SUB_API_NOTSET;
+       tmp_str = (char*) calloc(len+1, 1);
+       if (tmp_str == NULL) return SUB_API_NOTSET;
+       memcpy(tmp_str, driver, len+1);
+       tok = strtok(tmp_str, sep_str);
+       while (tok != NULL) {
+               for (i=0; i<usb_api_backend[api].nb_driver_names; i++) {
+                       if (safe_stricmp(tok, usb_api_backend[api].driver_name_list[i]) == 0) {
+                               free(tmp_str);
+                               return i;
+                       }
+               }
+               tok = strtok(NULL, sep_str);
+       }
+       free (tmp_str);
+       return SUB_API_NOTSET;
+}
+
+/*
+ * auto-claiming and auto-release helper functions
+ */
+static int auto_claim(struct libusb_transfer *transfer, int *interface_number, int api_type)
+{
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(
+               transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int current_interface = *interface_number;
+       int r = LIBUSB_SUCCESS;
+
+       switch(api_type) {
+       case USB_API_WINUSBX:
+       case USB_API_HID:
+               break;
+       default:
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       usbi_mutex_lock(&autoclaim_lock);
+       if (current_interface < 0)      // No serviceable interface was found
+       {
+               for (current_interface=0; current_interface<USB_MAXINTERFACES; current_interface++) {
+                       // Must claim an interface of the same API type
+                       if ( (priv->usb_interface[current_interface].apib->id == api_type)
+                         && (libusb_claim_interface(transfer->dev_handle, current_interface) == LIBUSB_SUCCESS) ) {
+                               usbi_dbg("auto-claimed interface %d for control request", current_interface);
+                               if (handle_priv->autoclaim_count[current_interface] != 0) {
+                                       usbi_warn(ctx, "program assertion failed - autoclaim_count was nonzero");
+                               }
+                               handle_priv->autoclaim_count[current_interface]++;
+                               break;
+                       }
+               }
+               if (current_interface == USB_MAXINTERFACES) {
+                       usbi_err(ctx, "could not auto-claim any interface");
+                       r = LIBUSB_ERROR_NOT_FOUND;
+               }
+       } else {
+               // If we have a valid interface that was autoclaimed, we must increment
+               // its autoclaim count so that we can prevent an early release.
+               if (handle_priv->autoclaim_count[current_interface] != 0) {
+                       handle_priv->autoclaim_count[current_interface]++;
+               }
+       }
+       usbi_mutex_unlock(&autoclaim_lock);
+
+       *interface_number = current_interface;
+       return r;
+
+}
+
+static void auto_release(struct usbi_transfer *itransfer)
+{
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       libusb_device_handle *dev_handle = transfer->dev_handle;
+       struct windows_device_handle_priv* handle_priv = _device_handle_priv(dev_handle);
+       int r;
+
+       usbi_mutex_lock(&autoclaim_lock);
+       if (handle_priv->autoclaim_count[transfer_priv->interface_number] > 0) {
+               handle_priv->autoclaim_count[transfer_priv->interface_number]--;
+               if (handle_priv->autoclaim_count[transfer_priv->interface_number] == 0) {
+                       r = libusb_release_interface(dev_handle, transfer_priv->interface_number);
+                       if (r == LIBUSB_SUCCESS) {
+                               usbi_dbg("auto-released interface %d", transfer_priv->interface_number);
+                       } else {
+                               usbi_dbg("failed to auto-release interface %d (%s)",
+                                       transfer_priv->interface_number, libusb_error_name((enum libusb_error)r));
+                       }
+               }
+       }
+       usbi_mutex_unlock(&autoclaim_lock);
+}
+
+/*
+ * init: libusb backend init function
+ *
+ * This function enumerates the HCDs (Host Controller Drivers) and populates our private HCD list
+ * In our implementation, we equate Windows' "HCD" to libusb's "bus". Note that bus is zero indexed.
+ * HCDs are not expected to change after init (might not hold true for hot pluggable USB PCI card?)
+ */
+static int windows_init(struct libusb_context *ctx)
+{
+       int i, r = LIBUSB_ERROR_OTHER;
+       OSVERSIONINFO os_version;
+       HANDLE semaphore;
+       char sem_name[11+1+8]; // strlen(libusb_init)+'\0'+(32-bit hex PID)
+
+       sprintf(sem_name, "libusb_init%08X", (unsigned int)GetCurrentProcessId()&0xFFFFFFFF);
+       semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
+       if (semaphore == NULL) {
+               usbi_err(ctx, "could not create semaphore: %s", windows_error_str(0));
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       // A successful wait brings our semaphore count to 0 (unsignaled)
+       // => any concurent wait stalls until the semaphore's release
+       if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
+               usbi_err(ctx, "failure to access semaphore: %s", windows_error_str(0));
+               CloseHandle(semaphore);
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       // NB: concurrent usage supposes that init calls are equally balanced with
+       // exit calls. If init is called more than exit, we will not exit properly
+       if ( ++concurrent_usage == 0 ) {        // First init?
+               // Detect OS version
+               memset(&os_version, 0, sizeof(OSVERSIONINFO));
+               os_version.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+               windows_version = WINDOWS_UNSUPPORTED;
+               if ((GetVersionEx(&os_version) != 0) && (os_version.dwPlatformId == VER_PLATFORM_WIN32_NT)) {
+                       if ((os_version.dwMajorVersion == 5) && (os_version.dwMinorVersion == 1)) {
+                               windows_version = WINDOWS_XP;
+                       } else if ((os_version.dwMajorVersion == 5) && (os_version.dwMinorVersion == 2)) {
+                               windows_version = WINDOWS_2003; // also includes XP 64
+                       } else if (os_version.dwMajorVersion >= 6) {
+                               windows_version = WINDOWS_VISTA_AND_LATER;
+                       }
+               }
+               if (windows_version == WINDOWS_UNSUPPORTED) {
+                       usbi_err(ctx, "This version of Windows is NOT supported");
+                       r = LIBUSB_ERROR_NOT_SUPPORTED;
+                       goto init_exit;
+               }
+
+               // We need a lock for proper auto-release
+               usbi_mutex_init(&autoclaim_lock, NULL);
+
+               // Initialize pollable file descriptors
+               init_polling();
+
+               // Load DLL imports
+               if (init_dlls() != LIBUSB_SUCCESS) {
+                       usbi_err(ctx, "could not resolve DLL functions");
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+
+               // Initialize the low level APIs (we don't care about errors at this stage)
+               for (i=0; i<USB_API_MAX; i++) {
+                       usb_api_backend[i].init(SUB_API_NOTSET, ctx);
+               }
+
+               // Because QueryPerformanceCounter might report different values when
+               // running on different cores, we create a separate thread for the timer
+               // calls, which we glue to the first core always to prevent timing discrepancies.
+               r = LIBUSB_ERROR_NO_MEM;
+               for (i = 0; i < 2; i++) {
+                       timer_request[i] = CreateEvent(NULL, TRUE, FALSE, NULL);
+                       if (timer_request[i] == NULL) {
+                               usbi_err(ctx, "could not create timer request event %d - aborting", i);
+                               goto init_exit;
+                       }
+               }
+               timer_response = CreateSemaphore(NULL, 0, MAX_TIMER_SEMAPHORES, NULL);
+               if (timer_response == NULL) {
+                       usbi_err(ctx, "could not create timer response semaphore - aborting");
+                       goto init_exit;
+               }
+               timer_mutex = CreateMutex(NULL, FALSE, NULL);
+               if (timer_mutex == NULL) {
+                       usbi_err(ctx, "could not create timer mutex - aborting");
+                       goto init_exit;
+               }
+               timer_thread = (HANDLE)_beginthreadex(NULL, 0, windows_clock_gettime_threaded, NULL, 0, NULL);
+               if (timer_thread == NULL) {
+                       usbi_err(ctx, "Unable to create timer thread - aborting");
+                       goto init_exit;
+               }
+               SetThreadAffinityMask(timer_thread, 0);
+
+               // Wait for timer thread to init before continuing.
+               if (WaitForSingleObject(timer_response, INFINITE) != WAIT_OBJECT_0) {
+                       usbi_err(ctx, "Failed to wait for timer thread to become ready - aborting");
+                       goto init_exit;
+               }
+
+               // Create a hash table to store session ids. Second parameter is better if prime
+               htab_create(ctx, HTAB_SIZE);
+       }
+       // At this stage, either we went through full init successfully, or didn't need to
+       r = LIBUSB_SUCCESS;
+
+init_exit: // Holds semaphore here.
+       if (!concurrent_usage && r != LIBUSB_SUCCESS) { // First init failed?
+               if (timer_thread) {
+                       SetEvent(timer_request[1]); // actually the signal to quit the thread.
+                       if (WAIT_OBJECT_0 != WaitForSingleObject(timer_thread, INFINITE)) {
+                               usbi_warn(ctx, "could not wait for timer thread to quit");
+                               TerminateThread(timer_thread, 1); // shouldn't happen, but we're destroying
+                                                                                                 // all objects it might have held anyway.
+                       }
+                       CloseHandle(timer_thread);
+                       timer_thread = NULL;
+               }
+               for (i = 0; i < 2; i++) {
+                       if (timer_request[i]) {
+                               CloseHandle(timer_request[i]);
+                               timer_request[i] = NULL;
+                       }
+               }
+               if (timer_response) {
+                       CloseHandle(timer_response);
+                       timer_response = NULL;
+               }
+               if (timer_mutex) {
+                       CloseHandle(timer_mutex);
+                       timer_mutex = NULL;
+               }
+               htab_destroy();
+       }
+
+       if (r != LIBUSB_SUCCESS)
+               --concurrent_usage; // Not expected to call libusb_exit if we failed.
+
+       ReleaseSemaphore(semaphore, 1, NULL);   // increase count back to 1
+       CloseHandle(semaphore);
+       return r;
+}
+
+/*
+ * HCD (root) hubs need to have their device descriptor manually populated
+ *
+ * Note that, like Microsoft does in the device manager, we populate the
+ * Vendor and Device ID for HCD hubs with the ones from the PCI HCD device.
+ */
+static int force_hcd_device_descriptor(struct libusb_device *dev)
+{
+       struct windows_device_priv *parent_priv, *priv = _device_priv(dev);
+       struct libusb_context *ctx = DEVICE_CTX(dev);
+       int vid, pid;
+
+       dev->num_configurations = 1;
+       priv->dev_descriptor.bLength = sizeof(USB_DEVICE_DESCRIPTOR);
+       priv->dev_descriptor.bDescriptorType = USB_DEVICE_DESCRIPTOR_TYPE;
+       priv->dev_descriptor.bNumConfigurations = 1;
+       priv->active_config = 1;
+
+       if (priv->parent_dev == NULL) {
+               usbi_err(ctx, "program assertion failed - HCD hub has no parent");
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+       parent_priv = _device_priv(priv->parent_dev);
+       if (sscanf(parent_priv->path, "\\\\.\\PCI#VEN_%04x&DEV_%04x%*s", &vid, &pid) == 2) {
+               priv->dev_descriptor.idVendor = (uint16_t)vid;
+               priv->dev_descriptor.idProduct = (uint16_t)pid;
+       } else {
+               usbi_warn(ctx, "could not infer VID/PID of HCD hub from '%s'", parent_priv->path);
+               priv->dev_descriptor.idVendor = 0x1d6b;         // Linux Foundation root hub
+               priv->dev_descriptor.idProduct = 1;
+       }
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * fetch and cache all the config descriptors through I/O
+ */
+static int cache_config_descriptors(struct libusb_device *dev, HANDLE hub_handle, char* device_id)
+{
+       DWORD size, ret_size;
+       struct libusb_context *ctx = DEVICE_CTX(dev);
+       struct windows_device_priv *priv = _device_priv(dev);
+       int r;
+       uint8_t i;
+
+       USB_CONFIGURATION_DESCRIPTOR_SHORT cd_buf_short;    // dummy request
+       PUSB_DESCRIPTOR_REQUEST cd_buf_actual = NULL;       // actual request
+       PUSB_CONFIGURATION_DESCRIPTOR cd_data = NULL;
+
+       if (dev->num_configurations == 0)
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       priv->config_descriptor = (unsigned char**) calloc(dev->num_configurations, sizeof(unsigned char*));
+       if (priv->config_descriptor == NULL)
+               return LIBUSB_ERROR_NO_MEM;
+       for (i=0; i<dev->num_configurations; i++)
+               priv->config_descriptor[i] = NULL;
+
+       for (i=0, r=LIBUSB_SUCCESS; ; i++)
+       {
+               // safe loop: release all dynamic resources
+               safe_free(cd_buf_actual);
+
+               // safe loop: end of loop condition
+               if ((i >= dev->num_configurations) || (r != LIBUSB_SUCCESS))
+                       break;
+
+               size = sizeof(USB_CONFIGURATION_DESCRIPTOR_SHORT);
+               memset(&cd_buf_short, 0, size);
+
+               cd_buf_short.req.ConnectionIndex = (ULONG)priv->port;
+               cd_buf_short.req.SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
+               cd_buf_short.req.SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
+               cd_buf_short.req.SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
+               cd_buf_short.req.SetupPacket.wIndex = i;
+               cd_buf_short.req.SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));
+
+               // Dummy call to get the required data size. Initial failures are reported as info rather
+               // than error as they can occur for non-penalizing situations, such as with some hubs.
+               if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, &cd_buf_short, size,
+                       &cd_buf_short, size, &ret_size, NULL)) {
+                       usbi_info(ctx, "could not access configuration descriptor (dummy) for '%s': %s", device_id, windows_error_str(0));
+                       LOOP_BREAK(LIBUSB_ERROR_IO);
+               }
+
+               if ((ret_size != size) || (cd_buf_short.data.wTotalLength < sizeof(USB_CONFIGURATION_DESCRIPTOR))) {
+                       usbi_info(ctx, "unexpected configuration descriptor size (dummy) for '%s'.", device_id);
+                       LOOP_BREAK(LIBUSB_ERROR_IO);
+               }
+
+               size = sizeof(USB_DESCRIPTOR_REQUEST) + cd_buf_short.data.wTotalLength;
+               if ((cd_buf_actual = (PUSB_DESCRIPTOR_REQUEST) calloc(1, size)) == NULL) {
+                       usbi_err(ctx, "could not allocate configuration descriptor buffer for '%s'.", device_id);
+                       LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
+               }
+               memset(cd_buf_actual, 0, size);
+
+               // Actual call
+               cd_buf_actual->ConnectionIndex = (ULONG)priv->port;
+               cd_buf_actual->SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
+               cd_buf_actual->SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
+               cd_buf_actual->SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
+               cd_buf_actual->SetupPacket.wIndex = i;
+               cd_buf_actual->SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));
+
+               if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, cd_buf_actual, size,
+                       cd_buf_actual, size, &ret_size, NULL)) {
+                       usbi_err(ctx, "could not access configuration descriptor (actual) for '%s': %s", device_id, windows_error_str(0));
+                       LOOP_BREAK(LIBUSB_ERROR_IO);
+               }
+
+               cd_data = (PUSB_CONFIGURATION_DESCRIPTOR)((UCHAR*)cd_buf_actual+sizeof(USB_DESCRIPTOR_REQUEST));
+
+               if ((size != ret_size) || (cd_data->wTotalLength != cd_buf_short.data.wTotalLength)) {
+                       usbi_err(ctx, "unexpected configuration descriptor size (actual) for '%s'.", device_id);
+                       LOOP_BREAK(LIBUSB_ERROR_IO);
+               }
+
+               if (cd_data->bDescriptorType != USB_CONFIGURATION_DESCRIPTOR_TYPE) {
+                       usbi_err(ctx, "not a configuration descriptor for '%s'", device_id);
+                       LOOP_BREAK(LIBUSB_ERROR_IO);
+               }
+
+               usbi_dbg("cached config descriptor %d (bConfigurationValue=%d, %d bytes)",
+                       i, cd_data->bConfigurationValue, cd_data->wTotalLength);
+
+               // Cache the descriptor
+               priv->config_descriptor[i] = (unsigned char*) malloc(cd_data->wTotalLength);
+               if (priv->config_descriptor[i] == NULL)
+                       return LIBUSB_ERROR_NO_MEM;
+               memcpy(priv->config_descriptor[i], cd_data, cd_data->wTotalLength);
+       }
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * Populate a libusb device structure
+ */
+static int init_device(struct libusb_device* dev, struct libusb_device* parent_dev,
+                                          uint8_t port_number, char* device_id, DWORD devinst)
+{
+       HANDLE handle;
+       DWORD size;
+       USB_NODE_CONNECTION_INFORMATION_EX conn_info;
+       struct windows_device_priv *priv, *parent_priv;
+       struct libusb_context *ctx = DEVICE_CTX(dev);
+       struct libusb_device* tmp_dev;
+       unsigned i;
+
+       if ((dev == NULL) || (parent_dev == NULL)) {
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+       priv = _device_priv(dev);
+       parent_priv = _device_priv(parent_dev);
+       if (parent_priv->apib->id != USB_API_HUB) {
+               usbi_warn(ctx, "parent for device '%s' is not a hub", device_id);
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       // It is possible for the parent hub not to have been initialized yet
+       // If that's the case, lookup the ancestors to set the bus number
+       if (parent_dev->bus_number == 0) {
+               for (i=2; ; i++) {
+                       tmp_dev = usbi_get_device_by_session_id(ctx, get_ancestor_session_id(devinst, i));
+                       if (tmp_dev == NULL) break;
+                       if (tmp_dev->bus_number != 0) {
+                               usbi_dbg("got bus number from ancestor #%d", i);
+                               parent_dev->bus_number = tmp_dev->bus_number;
+                               libusb_unref_device(tmp_dev);
+                               break;
+                       }
+                       libusb_unref_device(tmp_dev);
+               }
+       }
+       if (parent_dev->bus_number == 0) {
+               usbi_err(ctx, "program assertion failed: unable to find ancestor bus number for '%s'", device_id);
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+       dev->bus_number = parent_dev->bus_number;
+       priv->port = port_number;
+       dev->port_number = port_number;
+       priv->depth = parent_priv->depth + 1;
+       priv->parent_dev = parent_dev;
+       dev->parent_dev = parent_dev;
+
+       // If the device address is already set, we can stop here
+       if (dev->device_address != 0) {
+               return LIBUSB_SUCCESS;
+       }
+       memset(&conn_info, 0, sizeof(conn_info));
+       if (priv->depth != 0) { // Not a HCD hub
+               handle = CreateFileA(parent_priv->path, GENERIC_WRITE, FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
+                       FILE_FLAG_OVERLAPPED, NULL);
+               if (handle == INVALID_HANDLE_VALUE) {
+                       usbi_warn(ctx, "could not open hub %s: %s", parent_priv->path, windows_error_str(0));
+                       return LIBUSB_ERROR_ACCESS;
+               }
+               size = sizeof(conn_info);
+               conn_info.ConnectionIndex = (ULONG)port_number;
+               if (!DeviceIoControl(handle, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX, &conn_info, size,
+                       &conn_info, size, &size, NULL)) {
+                       usbi_warn(ctx, "could not get node connection information for device '%s': %s",
+                               device_id, windows_error_str(0));
+                       safe_closehandle(handle);
+                       return LIBUSB_ERROR_NO_DEVICE;
+               }
+               if (conn_info.ConnectionStatus == NoDeviceConnected) {
+                       usbi_err(ctx, "device '%s' is no longer connected!", device_id);
+                       safe_closehandle(handle);
+                       return LIBUSB_ERROR_NO_DEVICE;
+               }
+               memcpy(&priv->dev_descriptor, &(conn_info.DeviceDescriptor), sizeof(USB_DEVICE_DESCRIPTOR));
+               dev->num_configurations = priv->dev_descriptor.bNumConfigurations;
+               priv->active_config = conn_info.CurrentConfigurationValue;
+               usbi_dbg("found %d configurations (active conf: %d)", dev->num_configurations, priv->active_config);
+               // If we can't read the config descriptors, just set the number of confs to zero
+               if (cache_config_descriptors(dev, handle, device_id) != LIBUSB_SUCCESS) {
+                       dev->num_configurations = 0;
+                       priv->dev_descriptor.bNumConfigurations = 0;
+               }
+               safe_closehandle(handle);
+
+               if (conn_info.DeviceAddress > UINT8_MAX) {
+                       usbi_err(ctx, "program assertion failed: device address overflow");
+               }
+               dev->device_address = (uint8_t)conn_info.DeviceAddress + 1;
+               if (dev->device_address == 1) {
+                       usbi_err(ctx, "program assertion failed: device address collision with root hub");
+               }
+               switch (conn_info.Speed) {
+               case 0: dev->speed = LIBUSB_SPEED_LOW; break;
+               case 1: dev->speed = LIBUSB_SPEED_FULL; break;
+               case 2: dev->speed = LIBUSB_SPEED_HIGH; break;
+               case 3: dev->speed = LIBUSB_SPEED_SUPER; break;
+               default:
+                       usbi_warn(ctx, "Got unknown device speed %d", conn_info.Speed);
+                       break;
+               }
+       } else {
+               dev->device_address = 1;        // root hubs are set to use device number 1
+               force_hcd_device_descriptor(dev);
+       }
+
+       usbi_sanitize_device(dev);
+
+       usbi_dbg("(bus: %d, addr: %d, depth: %d, port: %d): '%s'",
+               dev->bus_number, dev->device_address, priv->depth, priv->port, device_id);
+
+       return LIBUSB_SUCCESS;
+}
+
+// Returns the api type, or 0 if not found/unsupported
+static void get_api_type(struct libusb_context *ctx, HDEVINFO *dev_info,
+       SP_DEVINFO_DATA *dev_info_data, int *api, int *sub_api)
+{
+       // Precedence for filter drivers vs driver is in the order of this array
+       struct driver_lookup lookup[3] = {
+               {"\0\0", SPDRP_SERVICE, "driver"},
+               {"\0\0", SPDRP_UPPERFILTERS, "upper filter driver"},
+               {"\0\0", SPDRP_LOWERFILTERS, "lower filter driver"}
+       };
+       DWORD size, reg_type;
+       unsigned k, l;
+       int i, j;
+
+       *api = USB_API_UNSUPPORTED;
+       *sub_api = SUB_API_NOTSET;
+       // Check the service & filter names to know the API we should use
+       for (k=0; k<3; k++) {
+               if (pSetupDiGetDeviceRegistryPropertyA(*dev_info, dev_info_data, lookup[k].reg_prop,
+                       &reg_type, (BYTE*)lookup[k].list, MAX_KEY_LENGTH, &size)) {
+                       // Turn the REG_SZ SPDRP_SERVICE into REG_MULTI_SZ
+                       if (lookup[k].reg_prop == SPDRP_SERVICE) {
+                               // our buffers are MAX_KEY_LENGTH+1 so we can overflow if needed
+                               lookup[k].list[safe_strlen(lookup[k].list)+1] = 0;
+                       }
+                       // MULTI_SZ is a pain to work with. Turn it into something much more manageable
+                       // NB: none of the driver names we check against contain LIST_SEPARATOR,
+                       // (currently ';'), so even if an unsuported one does, it's not an issue
+                       for (l=0; (lookup[k].list[l] != 0) || (lookup[k].list[l+1] != 0); l++) {
+                               if (lookup[k].list[l] == 0) {
+                                       lookup[k].list[l] = LIST_SEPARATOR;
+                               }
+                       }
+                       usbi_dbg("%s(s): %s", lookup[k].designation, lookup[k].list);
+               } else {
+                       if (GetLastError() != ERROR_INVALID_DATA) {
+                               usbi_dbg("could not access %s: %s", lookup[k].designation, windows_error_str(0));
+                       }
+                       lookup[k].list[0] = 0;
+               }
+       }
+
+       for (i=1; i<USB_API_MAX; i++) {
+               for (k=0; k<3; k++) {
+                       j = get_sub_api(lookup[k].list, i);
+                       if (j >= 0) {
+                               usbi_dbg("matched %s name against %s",
+                                       lookup[k].designation, (i!=USB_API_WINUSBX)?usb_api_backend[i].designation:sub_api_name[j]);
+                               *api = i;
+                               *sub_api = j;
+                               return;
+                       }
+               }
+       }
+}
+
+static int set_composite_interface(struct libusb_context* ctx, struct libusb_device* dev,
+                                                       char* dev_interface_path, char* device_id, int api, int sub_api)
+{
+       unsigned i;
+       struct windows_device_priv *priv = _device_priv(dev);
+       int interface_number;
+
+       if (priv->apib->id != USB_API_COMPOSITE) {
+               usbi_err(ctx, "program assertion failed: '%s' is not composite", device_id);
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+
+       // Because MI_## are not necessarily in sequential order (some composite
+       // devices will have only MI_00 & MI_03 for instance), we retrieve the actual
+       // interface number from the path's MI value
+       interface_number = 0;
+       for (i=0; device_id[i] != 0; ) {
+               if ( (device_id[i++] == 'M') && (device_id[i++] == 'I')
+                 && (device_id[i++] == '_') ) {
+                       interface_number = (device_id[i++] - '0')*10;
+                       interface_number += device_id[i] - '0';
+                       break;
+               }
+       }
+
+       if (device_id[i] == 0) {
+               usbi_warn(ctx, "failure to read interface number for %s. Using default value %d",
+                       device_id, interface_number);
+       }
+
+       if (priv->usb_interface[interface_number].path != NULL) {
+               if (api == USB_API_HID) {
+                       // HID devices can have multiple collections (COL##) for each MI_## interface
+                       usbi_dbg("interface[%d] already set - ignoring HID collection: %s",
+                               interface_number, device_id);
+                       return LIBUSB_ERROR_ACCESS;
+               }
+               // In other cases, just use the latest data
+               safe_free(priv->usb_interface[interface_number].path);
+       }
+
+       usbi_dbg("interface[%d] = %s", interface_number, dev_interface_path);
+       priv->usb_interface[interface_number].path = dev_interface_path;
+       priv->usb_interface[interface_number].apib = &usb_api_backend[api];
+       priv->usb_interface[interface_number].sub_api = sub_api;
+       if ((api == USB_API_HID) && (priv->hid == NULL)) {
+               priv->hid = (struct hid_device_priv*) calloc(1, sizeof(struct hid_device_priv));
+               if (priv->hid == NULL)
+                       return LIBUSB_ERROR_NO_MEM;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static int set_hid_interface(struct libusb_context* ctx, struct libusb_device* dev,
+                                                       char* dev_interface_path)
+{
+       int i;
+       struct windows_device_priv *priv = _device_priv(dev);
+
+       if (priv->hid == NULL) {
+               usbi_err(ctx, "program assertion failed: parent is not HID");
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+       if (priv->hid->nb_interfaces == USB_MAXINTERFACES) {
+               usbi_err(ctx, "program assertion failed: max USB interfaces reached for HID device");
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+       for (i=0; i<priv->hid->nb_interfaces; i++) {
+               if (safe_strcmp(priv->usb_interface[i].path, dev_interface_path) == 0) {
+                       usbi_dbg("interface[%d] already set to %s", i, dev_interface_path);
+                       return LIBUSB_SUCCESS;
+               }
+       }
+
+       priv->usb_interface[priv->hid->nb_interfaces].path = dev_interface_path;
+       priv->usb_interface[priv->hid->nb_interfaces].apib = &usb_api_backend[USB_API_HID];
+       usbi_dbg("interface[%d] = %s", priv->hid->nb_interfaces, dev_interface_path);
+       priv->hid->nb_interfaces++;
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * get_device_list: libusb backend device enumeration function
+ */
+static int windows_get_device_list(struct libusb_context *ctx, struct discovered_devs **_discdevs)
+{
+       struct discovered_devs *discdevs;
+       HDEVINFO dev_info = { 0 };
+       const char* usb_class[] = {"USB", "NUSB3", "IUSB3"};
+       SP_DEVINFO_DATA dev_info_data = { 0 };
+       SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
+       GUID hid_guid;
+#define MAX_ENUM_GUIDS 64
+       const GUID* guid[MAX_ENUM_GUIDS];
+#define HCD_PASS 0
+#define HUB_PASS 1
+#define GEN_PASS 2
+#define DEV_PASS 3
+#define HID_PASS 4
+       int r = LIBUSB_SUCCESS;
+       int api, sub_api;
+       size_t class_index = 0;
+       unsigned int nb_guids, pass, i, j, ancestor;
+       char path[MAX_PATH_LENGTH];
+       char strbuf[MAX_PATH_LENGTH];
+       struct libusb_device *dev, *parent_dev;
+       struct windows_device_priv *priv, *parent_priv;
+       char* dev_interface_path = NULL;
+       char* dev_id_path = NULL;
+       unsigned long session_id;
+       DWORD size, reg_type, port_nr, install_state;
+       HKEY key;
+       WCHAR guid_string_w[MAX_GUID_STRING_LENGTH];
+       GUID* if_guid;
+       LONG s;
+       // Keep a list of newly allocated devs to unref
+       libusb_device** unref_list;
+       unsigned int unref_size = 64;
+       unsigned int unref_cur = 0;
+
+       // PASS 1 : (re)enumerate HCDs (allows for HCD hotplug)
+       // PASS 2 : (re)enumerate HUBS
+       // PASS 3 : (re)enumerate generic USB devices (including driverless)
+       //           and list additional USB device interface GUIDs to explore
+       // PASS 4 : (re)enumerate master USB devices that have a device interface
+       // PASS 5+: (re)enumerate device interfaced GUIDs (including HID) and
+       //           set the device interfaces.
+
+       // Init the GUID table
+       guid[HCD_PASS] = &GUID_DEVINTERFACE_USB_HOST_CONTROLLER;
+       guid[HUB_PASS] = &GUID_DEVINTERFACE_USB_HUB;
+       guid[GEN_PASS] = NULL;
+       guid[DEV_PASS] = &GUID_DEVINTERFACE_USB_DEVICE;
+       HidD_GetHidGuid(&hid_guid);
+       guid[HID_PASS] = &hid_guid;
+       nb_guids = HID_PASS+1;
+
+       unref_list = (libusb_device**) calloc(unref_size, sizeof(libusb_device*));
+       if (unref_list == NULL) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       for (pass = 0; ((pass < nb_guids) && (r == LIBUSB_SUCCESS)); pass++) {
+//#define ENUM_DEBUG
+#ifdef ENUM_DEBUG
+               const char *passname[] = { "HCD", "HUB", "GEN", "DEV", "HID", "EXT" };
+               usbi_dbg("\n#### PROCESSING %ss %s", passname[(pass<=HID_PASS)?pass:HID_PASS+1],
+                       (pass!=GEN_PASS)?guid_to_string(guid[pass]):"");
+#endif
+               for (i = 0; ; i++) {
+                       // safe loop: free up any (unprotected) dynamic resource
+                       // NB: this is always executed before breaking the loop
+                       safe_free(dev_interface_details);
+                       safe_free(dev_interface_path);
+                       safe_free(dev_id_path);
+                       priv = parent_priv = NULL;
+                       dev = parent_dev = NULL;
+
+                       // Safe loop: end of loop conditions
+                       if (r != LIBUSB_SUCCESS) {
+                               break;
+                       }
+                       if ((pass == HCD_PASS) && (i == UINT8_MAX)) {
+                               usbi_warn(ctx, "program assertion failed - found more than %d buses, skipping the rest.", UINT8_MAX);
+                               break;
+                       }
+                       if (pass != GEN_PASS) {
+                               // Except for GEN, all passes deal with device interfaces
+                               dev_interface_details = get_interface_details(ctx, &dev_info, &dev_info_data, guid[pass], i);
+                               if (dev_interface_details == NULL) {
+                                       break;
+                               } else {
+                                       dev_interface_path = sanitize_path(dev_interface_details->DevicePath);
+                                       if (dev_interface_path == NULL) {
+                                               usbi_warn(ctx, "could not sanitize device interface path for '%s'", dev_interface_details->DevicePath);
+                                               continue;
+                                       }
+                               }
+                       } else {
+                               // Workaround for a Nec/Renesas USB 3.0 driver bug where root hubs are
+                               // being listed under the "NUSB3" PnP Symbolic Name rather than "USB".
+                               // The Intel USB 3.0 driver behaves similar, but uses "IUSB3"
+                               for (; class_index < ARRAYSIZE(usb_class); class_index++) {
+                                       if (get_devinfo_data(ctx, &dev_info, &dev_info_data, usb_class[class_index], i))
+                                               break;
+                                       i = 0;
+                               }
+                               if (class_index >= ARRAYSIZE(usb_class))
+                                       break;
+                       }
+
+                       // Read the Device ID path. This is what we'll use as UID
+                       // Note that if the device is plugged in a different port or hub, the Device ID changes
+                       if (CM_Get_Device_IDA(dev_info_data.DevInst, path, sizeof(path), 0) != CR_SUCCESS) {
+                               usbi_warn(ctx, "could not read the device id path for devinst %X, skipping",
+                                       dev_info_data.DevInst);
+                               continue;
+                       }
+                       dev_id_path = sanitize_path(path);
+                       if (dev_id_path == NULL) {
+                               usbi_warn(ctx, "could not sanitize device id path for devinst %X, skipping",
+                                       dev_info_data.DevInst);
+                               continue;
+                       }
+#ifdef ENUM_DEBUG
+                       usbi_dbg("PRO: %s", dev_id_path);
+#endif
+
+                       // The SPDRP_ADDRESS for USB devices is the device port number on the hub
+                       port_nr = 0;
+                       if ((pass >= HUB_PASS) && (pass <= GEN_PASS)) {
+                               if ( (!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_ADDRESS,
+                                       &reg_type, (BYTE*)&port_nr, 4, &size))
+                                 || (size != 4) ) {
+                                       usbi_warn(ctx, "could not retrieve port number for device '%s', skipping: %s",
+                                               dev_id_path, windows_error_str(0));
+                                       continue;
+                               }
+                       }
+
+                       // Set API to use or get additional data from generic pass
+                       api = USB_API_UNSUPPORTED;
+                       sub_api = SUB_API_NOTSET;
+                       switch (pass) {
+                       case HCD_PASS:
+                               break;
+                       case GEN_PASS:
+                               // We use the GEN pass to detect driverless devices...
+                               size = sizeof(strbuf);
+                               if (!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_DRIVER,
+                                       &reg_type, (BYTE*)strbuf, size, &size)) {
+                                               usbi_info(ctx, "The following device has no driver: '%s'", dev_id_path);
+                                               usbi_info(ctx, "libusb will not be able to access it.");
+                               }
+                               // ...and to add the additional device interface GUIDs
+                               key = pSetupDiOpenDevRegKey(dev_info, &dev_info_data, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ);
+                               if (key != INVALID_HANDLE_VALUE) {
+                                       size = sizeof(guid_string_w);
+                                       s = pRegQueryValueExW(key, L"DeviceInterfaceGUIDs", NULL, &reg_type,
+                                               (BYTE*)guid_string_w, &size);
+                                       pRegCloseKey(key);
+                                       if (s == ERROR_SUCCESS) {
+                                               if (nb_guids >= MAX_ENUM_GUIDS) {
+                                                       // If this assert is ever reported, grow a GUID table dynamically
+                                                       usbi_err(ctx, "program assertion failed: too many GUIDs");
+                                                       LOOP_BREAK(LIBUSB_ERROR_OVERFLOW);
+                                               }
+                                               if_guid = (GUID*) calloc(1, sizeof(GUID));
+                                               pCLSIDFromString(guid_string_w, if_guid);
+                                               guid[nb_guids++] = if_guid;
+                                               usbi_dbg("extra GUID: %s", guid_to_string(if_guid));
+                                       }
+                               }
+                               break;
+                       case HID_PASS:
+                               api = USB_API_HID;
+                               break;
+                       default:
+                               // Get the API type (after checking that the driver installation is OK)
+                               if ( (!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_INSTALL_STATE,
+                                       &reg_type, (BYTE*)&install_state, 4, &size))
+                                 || (size != 4) ){
+                                       usbi_warn(ctx, "could not detect installation state of driver for '%s': %s",
+                                               dev_id_path, windows_error_str(0));
+                               } else if (install_state != 0) {
+                                       usbi_warn(ctx, "driver for device '%s' is reporting an issue (code: %d) - skipping",
+                                               dev_id_path, install_state);
+                                       continue;
+                               }
+                               get_api_type(ctx, &dev_info, &dev_info_data, &api, &sub_api);
+                               break;
+                       }
+
+                       // Find parent device (for the passes that need it)
+                       switch (pass) {
+                       case HCD_PASS:
+                       case DEV_PASS:
+                       case HUB_PASS:
+                               break;
+                       default:
+                               // Go through the ancestors until we see a face we recognize
+                               parent_dev = NULL;
+                               for (ancestor = 1; parent_dev == NULL; ancestor++) {
+                                       session_id = get_ancestor_session_id(dev_info_data.DevInst, ancestor);
+                                       if (session_id == 0) {
+                                               break;
+                                       }
+                                       parent_dev = usbi_get_device_by_session_id(ctx, session_id);
+                               }
+                               if (parent_dev == NULL) {
+                                       usbi_dbg("unlisted ancestor for '%s' (non USB HID, newly connected, etc.) - ignoring", dev_id_path);
+                                       continue;
+                               }
+                               parent_priv = _device_priv(parent_dev);
+                               // virtual USB devices are also listed during GEN - don't process these yet
+                               if ( (pass == GEN_PASS) && (parent_priv->apib->id != USB_API_HUB) ) {
+                                       libusb_unref_device(parent_dev);
+                                       continue;
+                               }
+                               break;
+                       }
+
+                       // Create new or match existing device, using the (hashed) device_id as session id
+                       if (pass <= DEV_PASS) { // For subsequent passes, we'll lookup the parent
+                               // These are the passes that create "new" devices
+                               session_id = htab_hash(dev_id_path);
+                               dev = usbi_get_device_by_session_id(ctx, session_id);
+                               if (dev == NULL) {
+                                       if (pass == DEV_PASS) {
+                                               // This can occur if the OS only reports a newly plugged device after we started enum
+                                               usbi_warn(ctx, "'%s' was only detected in late pass (newly connected device?)"
+                                                       " - ignoring", dev_id_path);
+                                               continue;
+                                       }
+                                       usbi_dbg("allocating new device for session [%X]", session_id);
+                                       if ((dev = usbi_alloc_device(ctx, session_id)) == NULL) {
+                                               LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
+                                       }
+                                       windows_device_priv_init(dev);
+                               } else {
+                                       usbi_dbg("found existing device for session [%X] (%d.%d)",
+                                               session_id, dev->bus_number, dev->device_address);
+                               }
+                                // Keep track of devices that need unref
+                                unref_list[unref_cur++] = dev;
+                                if (unref_cur >= unref_size) {
+                                        unref_size += 64;
+                                        unref_list = usbi_reallocf(unref_list, unref_size*sizeof(libusb_device*));
+                                        if (unref_list == NULL) {
+                                                usbi_err(ctx, "could not realloc list for unref - aborting.");
+                                                LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
+                                        }
+                                }
+                               priv = _device_priv(dev);
+                       }
+
+                       // Setup device
+                       switch (pass) {
+                       case HCD_PASS:
+                               dev->bus_number = (uint8_t)(i + 1);     // bus 0 is reserved for disconnected
+                               dev->device_address = 0;
+                               dev->num_configurations = 0;
+                               priv->apib = &usb_api_backend[USB_API_HUB];
+                               priv->sub_api = SUB_API_NOTSET;
+                               priv->depth = UINT8_MAX;        // Overflow to 0 for HCD Hubs
+                               priv->path = dev_interface_path; dev_interface_path = NULL;
+                               break;
+                       case HUB_PASS:
+                       case DEV_PASS:
+                               // If the device has already been setup, don't do it again
+                               if (priv->path != NULL)
+                                       break;
+                               // Take care of API initialization
+                               priv->path = dev_interface_path; dev_interface_path = NULL;
+                               priv->apib = &usb_api_backend[api];
+                               priv->sub_api = sub_api;
+                               switch(api) {
+                               case USB_API_COMPOSITE:
+                               case USB_API_HUB:
+                                       break;
+                               case USB_API_HID:
+                                       priv->hid = calloc(1, sizeof(struct hid_device_priv));
+                                       if (priv->hid == NULL) {
+                                               LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
+                                       }
+                                       priv->hid->nb_interfaces = 0;
+                                       break;
+                               default:
+                                       // For other devices, the first interface is the same as the device
+                                       priv->usb_interface[0].path = (char*) calloc(safe_strlen(priv->path)+1, 1);
+                                       if (priv->usb_interface[0].path != NULL) {
+                                               safe_strcpy(priv->usb_interface[0].path, safe_strlen(priv->path)+1, priv->path);
+                                       } else {
+                                               usbi_warn(ctx, "could not duplicate interface path '%s'", priv->path);
+                                       }
+                                       // The following is needed if we want API calls to work for both simple
+                                       // and composite devices.
+                                       for(j=0; j<USB_MAXINTERFACES; j++) {
+                                               priv->usb_interface[j].apib = &usb_api_backend[api];
+                                       }
+                                       break;
+                               }
+                               break;
+                       case GEN_PASS:
+                               r = init_device(dev, parent_dev, (uint8_t)port_nr, dev_id_path, dev_info_data.DevInst);
+                               if (r == LIBUSB_SUCCESS) {
+                                       // Append device to the list of discovered devices
+                                       discdevs = discovered_devs_append(*_discdevs, dev);
+                                       if (!discdevs) {
+                                               LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
+                                       }
+                                       *_discdevs = discdevs;
+                               } else if (r == LIBUSB_ERROR_NO_DEVICE) {
+                                       // This can occur if the device was disconnected but Windows hasn't
+                                       // refreshed its enumeration yet - in that case, we ignore the device
+                                       r = LIBUSB_SUCCESS;
+                               }
+                               break;
+                       default:        // HID_PASS and later
+                               if (parent_priv->apib->id == USB_API_HID) {
+                                       usbi_dbg("setting HID interface for [%lX]:", parent_dev->session_data);
+                                       r = set_hid_interface(ctx, parent_dev, dev_interface_path);
+                                       if (r != LIBUSB_SUCCESS) LOOP_BREAK(r);
+                                       dev_interface_path = NULL;
+                               } else if (parent_priv->apib->id == USB_API_COMPOSITE) {
+                                       usbi_dbg("setting composite interface for [%lX]:", parent_dev->session_data);
+                                       switch (set_composite_interface(ctx, parent_dev, dev_interface_path, dev_id_path, api, sub_api)) {
+                                       case LIBUSB_SUCCESS:
+                                               dev_interface_path = NULL;
+                                               break;
+                                       case LIBUSB_ERROR_ACCESS:
+                                               // interface has already been set => make sure dev_interface_path is freed then
+                                               break;
+                                       default:
+                                               LOOP_BREAK(r);
+                                               break;
+                                       }
+                               }
+                               libusb_unref_device(parent_dev);
+                               break;
+                       }
+               }
+       }
+
+       // Free any additional GUIDs
+       for (pass = HID_PASS+1; pass < nb_guids; pass++) {
+               safe_free(guid[pass]);
+       }
+
+       // Unref newly allocated devs
+       for (i=0; i<unref_cur; i++) {
+               safe_unref_device(unref_list[i]);
+       }
+       safe_free(unref_list);
+
+       return r;
+}
+
+/*
+ * exit: libusb backend deinitialization function
+ */
+static void windows_exit(void)
+{
+       int i;
+       HANDLE semaphore;
+       char sem_name[11+1+8]; // strlen(libusb_init)+'\0'+(32-bit hex PID)
+
+       sprintf(sem_name, "libusb_init%08X", (unsigned int)GetCurrentProcessId()&0xFFFFFFFF);
+       semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
+       if (semaphore == NULL) {
+               return;
+       }
+
+       // A successful wait brings our semaphore count to 0 (unsignaled)
+       // => any concurent wait stalls until the semaphore release
+       if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
+               CloseHandle(semaphore);
+               return;
+       }
+
+       // Only works if exits and inits are balanced exactly
+       if (--concurrent_usage < 0) {   // Last exit
+               for (i=0; i<USB_API_MAX; i++) {
+                       usb_api_backend[i].exit(SUB_API_NOTSET);
+               }
+               exit_polling();
+
+               if (timer_thread) {
+                       SetEvent(timer_request[1]); // actually the signal to quit the thread.
+                       if (WAIT_OBJECT_0 != WaitForSingleObject(timer_thread, INFINITE)) {
+                               usbi_dbg("could not wait for timer thread to quit");
+                               TerminateThread(timer_thread, 1);
+                       }
+                       CloseHandle(timer_thread);
+                       timer_thread = NULL;
+               }
+               for (i = 0; i < 2; i++) {
+                       if (timer_request[i]) {
+                               CloseHandle(timer_request[i]);
+                               timer_request[i] = NULL;
+                       }
+               }
+               if (timer_response) {
+                       CloseHandle(timer_response);
+                       timer_response = NULL;
+               }
+               if (timer_mutex) {
+                       CloseHandle(timer_mutex);
+                       timer_mutex = NULL;
+               }
+               htab_destroy();
+       }
+
+       ReleaseSemaphore(semaphore, 1, NULL);   // increase count back to 1
+       CloseHandle(semaphore);
+}
+
+static int windows_get_device_descriptor(struct libusb_device *dev, unsigned char *buffer, int *host_endian)
+{
+       struct windows_device_priv *priv = _device_priv(dev);
+
+       memcpy(buffer, &(priv->dev_descriptor), DEVICE_DESC_LENGTH);
+       *host_endian = 0;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int windows_get_config_descriptor(struct libusb_device *dev, uint8_t config_index, unsigned char *buffer, size_t len, int *host_endian)
+{
+       struct windows_device_priv *priv = _device_priv(dev);
+       PUSB_CONFIGURATION_DESCRIPTOR config_header;
+       size_t size;
+
+       // config index is zero based
+       if (config_index >= dev->num_configurations)
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       if ((priv->config_descriptor == NULL) || (priv->config_descriptor[config_index] == NULL))
+               return LIBUSB_ERROR_NOT_FOUND;
+
+       config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptor[config_index];
+
+       size = min(config_header->wTotalLength, len);
+       memcpy(buffer, priv->config_descriptor[config_index], size);
+       *host_endian = 0;
+
+       return (int)size;
+}
+
+/*
+ * return the cached copy of the active config descriptor
+ */
+static int windows_get_active_config_descriptor(struct libusb_device *dev, unsigned char *buffer, size_t len, int *host_endian)
+{
+       struct windows_device_priv *priv = _device_priv(dev);
+
+       if (priv->active_config == 0)
+               return LIBUSB_ERROR_NOT_FOUND;
+
+       // config index is zero based
+       return windows_get_config_descriptor(dev, (uint8_t)(priv->active_config-1), buffer, len, host_endian);
+}
+
+static int windows_open(struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+
+       if (priv->apib == NULL) {
+               usbi_err(ctx, "program assertion failed - device is not initialized");
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+
+       return priv->apib->open(SUB_API_NOTSET, dev_handle);
+}
+
+static void windows_close(struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       priv->apib->close(SUB_API_NOTSET, dev_handle);
+}
+
+static int windows_get_configuration(struct libusb_device_handle *dev_handle, int *config)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       if (priv->active_config == 0) {
+               *config = 0;
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       *config = priv->active_config;
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * from http://msdn.microsoft.com/en-us/library/ms793522.aspx: "The port driver
+ * does not currently expose a service that allows higher-level drivers to set
+ * the configuration."
+ */
+static int windows_set_configuration(struct libusb_device_handle *dev_handle, int config)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       int r = LIBUSB_SUCCESS;
+
+       if (config >= USB_MAXCONFIG)
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_OUT |
+               LIBUSB_REQUEST_TYPE_STANDARD | LIBUSB_RECIPIENT_DEVICE,
+               LIBUSB_REQUEST_SET_CONFIGURATION, (uint16_t)config,
+               0, NULL, 0, 1000);
+
+       if (r == LIBUSB_SUCCESS) {
+               priv->active_config = (uint8_t)config;
+       }
+       return r;
+}
+
+static int windows_claim_interface(struct libusb_device_handle *dev_handle, int iface)
+{
+       int r = LIBUSB_SUCCESS;
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       if (iface >= USB_MAXINTERFACES)
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       safe_free(priv->usb_interface[iface].endpoint);
+       priv->usb_interface[iface].nb_endpoints= 0;
+
+       r = priv->apib->claim_interface(SUB_API_NOTSET, dev_handle, iface);
+
+       if (r == LIBUSB_SUCCESS) {
+               r = windows_assign_endpoints(dev_handle, iface, 0);
+       }
+
+       return r;
+}
+
+static int windows_set_interface_altsetting(struct libusb_device_handle *dev_handle, int iface, int altsetting)
+{
+       int r = LIBUSB_SUCCESS;
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       safe_free(priv->usb_interface[iface].endpoint);
+       priv->usb_interface[iface].nb_endpoints= 0;
+
+       r = priv->apib->set_interface_altsetting(SUB_API_NOTSET, dev_handle, iface, altsetting);
+
+       if (r == LIBUSB_SUCCESS) {
+               r = windows_assign_endpoints(dev_handle, iface, altsetting);
+       }
+
+       return r;
+}
+
+static int windows_release_interface(struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       return priv->apib->release_interface(SUB_API_NOTSET, dev_handle, iface);
+}
+
+static int windows_clear_halt(struct libusb_device_handle *dev_handle, unsigned char endpoint)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       return priv->apib->clear_halt(SUB_API_NOTSET, dev_handle, endpoint);
+}
+
+static int windows_reset_device(struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       return priv->apib->reset_device(SUB_API_NOTSET, dev_handle);
+}
+
+// The 3 functions below are unlikely to ever get supported on Windows
+static int windows_kernel_driver_active(struct libusb_device_handle *dev_handle, int iface)
+{
+       return LIBUSB_ERROR_NOT_SUPPORTED;
+}
+
+static int windows_attach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
+{
+       return LIBUSB_ERROR_NOT_SUPPORTED;
+}
+
+static int windows_detach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
+{
+       return LIBUSB_ERROR_NOT_SUPPORTED;
+}
+
+static void windows_destroy_device(struct libusb_device *dev)
+{
+       windows_device_priv_release(dev);
+}
+
+static void windows_clear_transfer_priv(struct usbi_transfer *itransfer)
+{
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+
+       usbi_free_fd(&transfer_priv->pollable_fd);
+       safe_free(transfer_priv->hid_buffer);
+       // When auto claim is in use, attempt to release the auto-claimed interface
+       auto_release(itransfer);
+}
+
+static int submit_bulk_transfer(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int r;
+
+       r = priv->apib->submit_bulk_transfer(SUB_API_NOTSET, itransfer);
+       if (r != LIBUSB_SUCCESS) {
+               return r;
+       }
+
+       usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
+               (short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));
+
+       itransfer->flags |= USBI_TRANSFER_UPDATED_FDS;
+       return LIBUSB_SUCCESS;
+}
+
+static int submit_iso_transfer(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int r;
+
+       r = priv->apib->submit_iso_transfer(SUB_API_NOTSET, itransfer);
+       if (r != LIBUSB_SUCCESS) {
+               return r;
+       }
+
+       usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
+               (short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));
+
+       itransfer->flags |= USBI_TRANSFER_UPDATED_FDS;
+       return LIBUSB_SUCCESS;
+}
+
+static int submit_control_transfer(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int r;
+
+       r = priv->apib->submit_control_transfer(SUB_API_NOTSET, itransfer);
+       if (r != LIBUSB_SUCCESS) {
+               return r;
+       }
+
+       usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd, POLLIN);
+
+       itransfer->flags |= USBI_TRANSFER_UPDATED_FDS;
+       return LIBUSB_SUCCESS;
+
+}
+
+static int windows_submit_transfer(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+
+       switch (transfer->type) {
+       case LIBUSB_TRANSFER_TYPE_CONTROL:
+               return submit_control_transfer(itransfer);
+       case LIBUSB_TRANSFER_TYPE_BULK:
+       case LIBUSB_TRANSFER_TYPE_INTERRUPT:
+               if (IS_XFEROUT(transfer) &&
+                   transfer->flags & LIBUSB_TRANSFER_ADD_ZERO_PACKET)
+                       return LIBUSB_ERROR_NOT_SUPPORTED;
+               return submit_bulk_transfer(itransfer);
+       case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
+               return submit_iso_transfer(itransfer);
+       default:
+               usbi_err(TRANSFER_CTX(transfer), "unknown endpoint type %d", transfer->type);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+}
+
+static int windows_abort_control(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+
+       return priv->apib->abort_control(SUB_API_NOTSET, itransfer);
+}
+
+static int windows_abort_transfers(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+
+       return priv->apib->abort_transfers(SUB_API_NOTSET, itransfer);
+}
+
+static int windows_cancel_transfer(struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+
+       switch (transfer->type) {
+       case LIBUSB_TRANSFER_TYPE_CONTROL:
+               return windows_abort_control(itransfer);
+       case LIBUSB_TRANSFER_TYPE_BULK:
+       case LIBUSB_TRANSFER_TYPE_INTERRUPT:
+       case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
+               return windows_abort_transfers(itransfer);
+       default:
+               usbi_err(ITRANSFER_CTX(itransfer), "unknown endpoint type %d", transfer->type);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+}
+
+static void windows_transfer_callback(struct usbi_transfer *itransfer, uint32_t io_result, uint32_t io_size)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int status, istatus;
+
+       usbi_dbg("handling I/O completion with errcode %d, size %d", io_result, io_size);
+
+       switch(io_result) {
+       case NO_ERROR:
+               status = priv->apib->copy_transfer_data(SUB_API_NOTSET, itransfer, io_size);
+               break;
+       case ERROR_GEN_FAILURE:
+               usbi_dbg("detected endpoint stall");
+               status = LIBUSB_TRANSFER_STALL;
+               break;
+       case ERROR_SEM_TIMEOUT:
+               usbi_dbg("detected semaphore timeout");
+               status = LIBUSB_TRANSFER_TIMED_OUT;
+               break;
+       case ERROR_OPERATION_ABORTED:
+               istatus = priv->apib->copy_transfer_data(SUB_API_NOTSET, itransfer, io_size);
+               if (istatus != LIBUSB_TRANSFER_COMPLETED) {
+                       usbi_dbg("Failed to copy partial data in aborted operation: %d", istatus);
+               }
+               if (itransfer->flags & USBI_TRANSFER_TIMED_OUT) {
+                       usbi_dbg("detected timeout");
+                       status = LIBUSB_TRANSFER_TIMED_OUT;
+               } else {
+                       usbi_dbg("detected operation aborted");
+                       status = LIBUSB_TRANSFER_CANCELLED;
+               }
+               break;
+       default:
+               usbi_err(ITRANSFER_CTX(itransfer), "detected I/O error %d: %s", io_result, windows_error_str(io_result));
+               status = LIBUSB_TRANSFER_ERROR;
+               break;
+       }
+       windows_clear_transfer_priv(itransfer); // Cancel polling
+       usbi_handle_transfer_completion(itransfer, (enum libusb_transfer_status)status);
+}
+
+static void windows_handle_callback (struct usbi_transfer *itransfer, uint32_t io_result, uint32_t io_size)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+
+       switch (transfer->type) {
+       case LIBUSB_TRANSFER_TYPE_CONTROL:
+       case LIBUSB_TRANSFER_TYPE_BULK:
+       case LIBUSB_TRANSFER_TYPE_INTERRUPT:
+       case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
+               windows_transfer_callback (itransfer, io_result, io_size);
+               break;
+       default:
+               usbi_err(ITRANSFER_CTX(itransfer), "unknown endpoint type %d", transfer->type);
+       }
+}
+
+static int windows_handle_events(struct libusb_context *ctx, struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready)
+{
+       struct windows_transfer_priv* transfer_priv = NULL;
+       POLL_NFDS_TYPE i = 0;
+       bool found = false;
+       struct usbi_transfer *transfer;
+       DWORD io_size, io_result;
+
+       usbi_mutex_lock(&ctx->open_devs_lock);
+       for (i = 0; i < nfds && num_ready > 0; i++) {
+
+               usbi_dbg("checking fd %d with revents = %04x", fds[i].fd, fds[i].revents);
+
+               if (!fds[i].revents) {
+                       continue;
+               }
+
+               num_ready--;
+
+               // Because a Windows OVERLAPPED is used for poll emulation,
+               // a pollable fd is created and stored with each transfer
+               usbi_mutex_lock(&ctx->flying_transfers_lock);
+               list_for_each_entry(transfer, &ctx->flying_transfers, list, struct usbi_transfer) {
+                       transfer_priv = usbi_transfer_get_os_priv(transfer);
+                       if (transfer_priv->pollable_fd.fd == fds[i].fd) {
+                               found = true;
+                               break;
+                       }
+               }
+               usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
+               if (found) {
+                       // Handle async requests that completed synchronously first
+                       if (HasOverlappedIoCompletedSync(transfer_priv->pollable_fd.overlapped)) {
+                               io_result = NO_ERROR;
+                               io_size = (DWORD)transfer_priv->pollable_fd.overlapped->InternalHigh;
+                       // Regular async overlapped
+                       } else if (GetOverlappedResult(transfer_priv->pollable_fd.handle,
+                               transfer_priv->pollable_fd.overlapped, &io_size, false)) {
+                               io_result = NO_ERROR;
+                       } else {
+                               io_result = GetLastError();
+                       }
+                       usbi_remove_pollfd(ctx, transfer_priv->pollable_fd.fd);
+                       // let handle_callback free the event using the transfer wfd
+                       // If you don't use the transfer wfd, you run a risk of trying to free a
+                       // newly allocated wfd that took the place of the one from the transfer.
+                       windows_handle_callback(transfer, io_result, io_size);
+               } else {
+                       usbi_err(ctx, "could not find a matching transfer for fd %x", fds[i]);
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+       }
+
+       usbi_mutex_unlock(&ctx->open_devs_lock);
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * Monotonic and real time functions
+ */
+unsigned __stdcall windows_clock_gettime_threaded(void* param)
+{
+       LARGE_INTEGER hires_counter, li_frequency;
+       LONG nb_responses;
+       int timer_index;
+
+       // Init - find out if we have access to a monotonic (hires) timer
+       if (!QueryPerformanceFrequency(&li_frequency)) {
+               usbi_dbg("no hires timer available on this platform");
+               hires_frequency = 0;
+               hires_ticks_to_ps = UINT64_C(0);
+       } else {
+               hires_frequency = li_frequency.QuadPart;
+               // The hires frequency can go as high as 4 GHz, so we'll use a conversion
+               // to picoseconds to compute the tv_nsecs part in clock_gettime
+               hires_ticks_to_ps = UINT64_C(1000000000000) / hires_frequency;
+               usbi_dbg("hires timer available (Frequency: %"PRIu64" Hz)", hires_frequency);
+       }
+
+       // Signal windows_init() that we're ready to service requests
+       if (ReleaseSemaphore(timer_response, 1, NULL) == 0) {
+               usbi_dbg("unable to release timer semaphore: %s", windows_error_str(0));
+       }
+
+       // Main loop - wait for requests
+       while (1) {
+               timer_index = WaitForMultipleObjects(2, timer_request, FALSE, INFINITE) - WAIT_OBJECT_0;
+               if ( (timer_index != 0) && (timer_index != 1) ) {
+                       usbi_dbg("failure to wait on requests: %s", windows_error_str(0));
+                       continue;
+               }
+               if (request_count[timer_index] == 0) {
+                       // Request already handled
+                       ResetEvent(timer_request[timer_index]);
+                       // There's still a possiblity that a thread sends a request between the
+                       // time we test request_count[] == 0 and we reset the event, in which case
+                       // the request would be ignored. The simple solution to that is to test
+                       // request_count again and process requests if non zero.
+                       if (request_count[timer_index] == 0)
+                               continue;
+               }
+               switch (timer_index) {
+               case 0:
+                       WaitForSingleObject(timer_mutex, INFINITE);
+                       // Requests to this thread are for hires always
+                       if (QueryPerformanceCounter(&hires_counter) != 0) {
+                               timer_tp.tv_sec = (long)(hires_counter.QuadPart / hires_frequency);
+                               timer_tp.tv_nsec = (long)(((hires_counter.QuadPart % hires_frequency)/1000) * hires_ticks_to_ps);
+                       } else {
+                               // Fallback to real-time if we can't get monotonic value
+                               // Note that real-time clock does not wait on the mutex or this thread.
+                               windows_clock_gettime(USBI_CLOCK_REALTIME, &timer_tp);
+                       }
+                       ReleaseMutex(timer_mutex);
+
+                       nb_responses = InterlockedExchange((LONG*)&request_count[0], 0);
+                       if ( (nb_responses)
+                         && (ReleaseSemaphore(timer_response, nb_responses, NULL) == 0) ) {
+                               usbi_dbg("unable to release timer semaphore: %s", windows_error_str(0));
+                       }
+                       continue;
+               case 1: // time to quit
+                       usbi_dbg("timer thread quitting");
+                       return 0;
+               }
+       }
+}
+
+static int windows_clock_gettime(int clk_id, struct timespec *tp)
+{
+       FILETIME filetime;
+       ULARGE_INTEGER rtime;
+       DWORD r;
+       switch(clk_id) {
+       case USBI_CLOCK_MONOTONIC:
+               if (hires_frequency != 0) {
+                       while (1) {
+                               InterlockedIncrement((LONG*)&request_count[0]);
+                               SetEvent(timer_request[0]);
+                               r = WaitForSingleObject(timer_response, TIMER_REQUEST_RETRY_MS);
+                               switch(r) {
+                               case WAIT_OBJECT_0:
+                                       WaitForSingleObject(timer_mutex, INFINITE);
+                                       *tp = timer_tp;
+                                       ReleaseMutex(timer_mutex);
+                                       return LIBUSB_SUCCESS;
+                               case WAIT_TIMEOUT:
+                                       usbi_dbg("could not obtain a timer value within reasonable timeframe - too much load?");
+                                       break; // Retry until successful
+                               default:
+                                       usbi_dbg("WaitForSingleObject failed: %s", windows_error_str(0));
+                                       return LIBUSB_ERROR_OTHER;
+                               }
+                       }
+               }
+               // Fall through and return real-time if monotonic was not detected @ timer init
+       case USBI_CLOCK_REALTIME:
+               // We follow http://msdn.microsoft.com/en-us/library/ms724928%28VS.85%29.aspx
+               // with a predef epoch_time to have an epoch that starts at 1970.01.01 00:00
+               // Note however that our resolution is bounded by the Windows system time
+               // functions and is at best of the order of 1 ms (or, usually, worse)
+               GetSystemTimeAsFileTime(&filetime);
+               rtime.LowPart = filetime.dwLowDateTime;
+               rtime.HighPart = filetime.dwHighDateTime;
+               rtime.QuadPart -= epoch_time;
+               tp->tv_sec = (long)(rtime.QuadPart / 10000000);
+               tp->tv_nsec = (long)((rtime.QuadPart % 10000000)*100);
+               return LIBUSB_SUCCESS;
+       default:
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+}
+
+
+// NB: MSVC6 does not support named initializers.
+const struct usbi_os_backend windows_backend = {
+       "Windows",
+       USBI_CAP_HAS_HID_ACCESS,
+       windows_init,
+       windows_exit,
+
+       windows_get_device_list,
+       NULL,                           /* hotplug_poll */
+       windows_open,
+       windows_close,
+
+       windows_get_device_descriptor,
+       windows_get_active_config_descriptor,
+       windows_get_config_descriptor,
+       NULL,                           /* get_config_descriptor_by_value() */
+
+       windows_get_configuration,
+       windows_set_configuration,
+       windows_claim_interface,
+       windows_release_interface,
+
+       windows_set_interface_altsetting,
+       windows_clear_halt,
+       windows_reset_device,
+
+       windows_kernel_driver_active,
+       windows_detach_kernel_driver,
+       windows_attach_kernel_driver,
+
+       windows_destroy_device,
+
+       windows_submit_transfer,
+       windows_cancel_transfer,
+       windows_clear_transfer_priv,
+
+       windows_handle_events,
+
+       windows_clock_gettime,
+#if defined(USBI_TIMERFD_AVAILABLE)
+       NULL,
+#endif
+       sizeof(struct windows_device_priv),
+       sizeof(struct windows_device_handle_priv),
+       sizeof(struct windows_transfer_priv),
+       0,
+};
+
+
+/*
+ * USB API backends
+ */
+static int unsupported_init(int sub_api, struct libusb_context *ctx) {
+       return LIBUSB_SUCCESS;
+}
+static int unsupported_exit(int sub_api) {
+       return LIBUSB_SUCCESS;
+}
+static int unsupported_open(int sub_api, struct libusb_device_handle *dev_handle) {
+       PRINT_UNSUPPORTED_API(open);
+}
+static void unsupported_close(int sub_api, struct libusb_device_handle *dev_handle) {
+       usbi_dbg("unsupported API call for 'close'");
+}
+static int unsupported_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface) {
+       PRINT_UNSUPPORTED_API(configure_endpoints);
+}
+static int unsupported_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface) {
+       PRINT_UNSUPPORTED_API(claim_interface);
+}
+static int unsupported_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting) {
+       PRINT_UNSUPPORTED_API(set_interface_altsetting);
+}
+static int unsupported_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface) {
+       PRINT_UNSUPPORTED_API(release_interface);
+}
+static int unsupported_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint) {
+       PRINT_UNSUPPORTED_API(clear_halt);
+}
+static int unsupported_reset_device(int sub_api, struct libusb_device_handle *dev_handle) {
+       PRINT_UNSUPPORTED_API(reset_device);
+}
+static int unsupported_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       PRINT_UNSUPPORTED_API(submit_bulk_transfer);
+}
+static int unsupported_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       PRINT_UNSUPPORTED_API(submit_iso_transfer);
+}
+static int unsupported_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       PRINT_UNSUPPORTED_API(submit_control_transfer);
+}
+static int unsupported_abort_control(int sub_api, struct usbi_transfer *itransfer) {
+       PRINT_UNSUPPORTED_API(abort_control);
+}
+static int unsupported_abort_transfers(int sub_api, struct usbi_transfer *itransfer) {
+       PRINT_UNSUPPORTED_API(abort_transfers);
+}
+static int unsupported_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size) {
+       PRINT_UNSUPPORTED_API(copy_transfer_data);
+}
+static int common_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface) {
+       return LIBUSB_SUCCESS;
+}
+// These names must be uppercase
+const char* hub_driver_names[] = {"USBHUB", "USBHUB3", "USB3HUB", "NUSB3HUB", "RUSB3HUB", "FLXHCIH", "TIHUB3", "ETRONHUB3", "VIAHUB3", "ASMTHUB3", "IUSB3HUB", "VUSB3HUB", "AMDHUB30"};
+const char* composite_driver_names[] = {"USBCCGP"};
+const char* winusbx_driver_names[] = WINUSBX_DRV_NAMES;
+const char* hid_driver_names[] = {"HIDUSB", "MOUHID", "KBDHID"};
+const struct windows_usb_api_backend usb_api_backend[USB_API_MAX] = {
+       {
+               USB_API_UNSUPPORTED,
+               "Unsupported API",
+               NULL,
+               0,
+               unsupported_init,
+               unsupported_exit,
+               unsupported_open,
+               unsupported_close,
+               unsupported_configure_endpoints,
+               unsupported_claim_interface,
+               unsupported_set_interface_altsetting,
+               unsupported_release_interface,
+               unsupported_clear_halt,
+               unsupported_reset_device,
+               unsupported_submit_bulk_transfer,
+               unsupported_submit_iso_transfer,
+               unsupported_submit_control_transfer,
+               unsupported_abort_control,
+               unsupported_abort_transfers,
+               unsupported_copy_transfer_data,
+       }, {
+               USB_API_HUB,
+               "HUB API",
+               hub_driver_names,
+               ARRAYSIZE(hub_driver_names),
+               unsupported_init,
+               unsupported_exit,
+               unsupported_open,
+               unsupported_close,
+               unsupported_configure_endpoints,
+               unsupported_claim_interface,
+               unsupported_set_interface_altsetting,
+               unsupported_release_interface,
+               unsupported_clear_halt,
+               unsupported_reset_device,
+               unsupported_submit_bulk_transfer,
+               unsupported_submit_iso_transfer,
+               unsupported_submit_control_transfer,
+               unsupported_abort_control,
+               unsupported_abort_transfers,
+               unsupported_copy_transfer_data,
+       }, {
+               USB_API_COMPOSITE,
+               "Composite API",
+               composite_driver_names,
+               ARRAYSIZE(composite_driver_names),
+               composite_init,
+               composite_exit,
+               composite_open,
+               composite_close,
+               common_configure_endpoints,
+               composite_claim_interface,
+               composite_set_interface_altsetting,
+               composite_release_interface,
+               composite_clear_halt,
+               composite_reset_device,
+               composite_submit_bulk_transfer,
+               composite_submit_iso_transfer,
+               composite_submit_control_transfer,
+               composite_abort_control,
+               composite_abort_transfers,
+               composite_copy_transfer_data,
+       }, {
+               USB_API_WINUSBX,
+               "WinUSB-like APIs",
+               winusbx_driver_names,
+               ARRAYSIZE(winusbx_driver_names),
+               winusbx_init,
+               winusbx_exit,
+               winusbx_open,
+               winusbx_close,
+               winusbx_configure_endpoints,
+               winusbx_claim_interface,
+               winusbx_set_interface_altsetting,
+               winusbx_release_interface,
+               winusbx_clear_halt,
+               winusbx_reset_device,
+               winusbx_submit_bulk_transfer,
+               unsupported_submit_iso_transfer,
+               winusbx_submit_control_transfer,
+               winusbx_abort_control,
+               winusbx_abort_transfers,
+               winusbx_copy_transfer_data,
+       }, {
+               USB_API_HID,
+               "HID API",
+               hid_driver_names,
+               ARRAYSIZE(hid_driver_names),
+               hid_init,
+               hid_exit,
+               hid_open,
+               hid_close,
+               common_configure_endpoints,
+               hid_claim_interface,
+               hid_set_interface_altsetting,
+               hid_release_interface,
+               hid_clear_halt,
+               hid_reset_device,
+               hid_submit_bulk_transfer,
+               unsupported_submit_iso_transfer,
+               hid_submit_control_transfer,
+               hid_abort_transfers,
+               hid_abort_transfers,
+               hid_copy_transfer_data,
+       },
+};
+
+
+/*
+ * WinUSB-like (WinUSB, libusb0/libusbK through libusbk DLL) API functions
+ */
+#define WinUSBX_Set(fn) do { if (native_winusb) WinUSBX[i].fn = (WinUsb_##fn##_t) GetProcAddress(h, "WinUsb_" #fn); \
+       else pLibK_GetProcAddress((PVOID*)&WinUSBX[i].fn, i, KUSB_FNID_##fn); } while (0)
+
+static int winusbx_init(int sub_api, struct libusb_context *ctx)
+{
+       HMODULE h = NULL;
+       bool native_winusb = false;
+       int i;
+       KLIB_VERSION LibK_Version;
+       LibK_GetProcAddress_t pLibK_GetProcAddress = NULL;
+       LibK_GetVersion_t pLibK_GetVersion = NULL;
+
+       h = GetModuleHandleA("libusbK");
+       if (h == NULL) {
+               h = LoadLibraryA("libusbK");
+       }
+       if (h == NULL) {
+               usbi_info(ctx, "libusbK DLL is not available, will use native WinUSB");
+               h = GetModuleHandleA("WinUSB");
+               if (h == NULL) {
+                       h = LoadLibraryA("WinUSB");
+               }               if (h == NULL) {
+                       usbi_warn(ctx, "WinUSB DLL is not available either,\n"
+                               "you will not be able to access devices outside of enumeration");
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+       } else {
+               usbi_dbg("using libusbK DLL for universal access");
+               pLibK_GetVersion = (LibK_GetVersion_t) GetProcAddress(h, "LibK_GetVersion");
+               if (pLibK_GetVersion != NULL) {
+                       pLibK_GetVersion(&LibK_Version);
+                       usbi_dbg("libusbK version: %d.%d.%d.%d", LibK_Version.Major, LibK_Version.Minor,
+                               LibK_Version.Micro, LibK_Version.Nano);
+               }
+               pLibK_GetProcAddress = (LibK_GetProcAddress_t) GetProcAddress(h, "LibK_GetProcAddress");
+               if (pLibK_GetProcAddress == NULL) {
+                       usbi_err(ctx, "LibK_GetProcAddress() not found in libusbK DLL");
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+       }
+       native_winusb = (pLibK_GetProcAddress == NULL);
+       for (i=SUB_API_LIBUSBK; i<SUB_API_MAX; i++) {
+               WinUSBX_Set(AbortPipe);
+               WinUSBX_Set(ControlTransfer);
+               WinUSBX_Set(FlushPipe);
+               WinUSBX_Set(Free);
+               WinUSBX_Set(GetAssociatedInterface);
+               WinUSBX_Set(GetCurrentAlternateSetting);
+               WinUSBX_Set(GetDescriptor);
+               WinUSBX_Set(GetOverlappedResult);
+               WinUSBX_Set(GetPipePolicy);
+               WinUSBX_Set(GetPowerPolicy);
+               WinUSBX_Set(Initialize);
+               WinUSBX_Set(QueryDeviceInformation);
+               WinUSBX_Set(QueryInterfaceSettings);
+               WinUSBX_Set(QueryPipe);
+               WinUSBX_Set(ReadPipe);
+               WinUSBX_Set(ResetPipe);
+               WinUSBX_Set(SetCurrentAlternateSetting);
+               WinUSBX_Set(SetPipePolicy);
+               WinUSBX_Set(SetPowerPolicy);
+               WinUSBX_Set(WritePipe);
+               if (!native_winusb) {
+                       WinUSBX_Set(ResetDevice);
+               }
+               if (WinUSBX[i].Initialize != NULL) {
+                       WinUSBX[i].initialized = true;
+                       usbi_dbg("initalized sub API %s", sub_api_name[i]);
+               } else {
+                       usbi_warn(ctx, "Failed to initalize sub API %s", sub_api_name[i]);
+                       WinUSBX[i].initialized = false;
+               }
+       }
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_exit(int sub_api)
+{
+       return LIBUSB_SUCCESS;
+}
+
+// NB: open and close must ensure that they only handle interface of
+// the right API type, as these functions can be called wholesale from
+// composite_open(), with interfaces belonging to different APIs
+static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+
+       HANDLE file_handle;
+       int i;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       // WinUSB requires a seperate handle for each interface
+       for (i = 0; i < USB_MAXINTERFACES; i++) {
+               if ( (priv->usb_interface[i].path != NULL)
+                 && (priv->usb_interface[i].apib->id == USB_API_WINUSBX) ) {
+                       file_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
+                               NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
+                       if (file_handle == INVALID_HANDLE_VALUE) {
+                               usbi_err(ctx, "could not open device %s (interface %d): %s", priv->usb_interface[i].path, i, windows_error_str(0));
+                               switch(GetLastError()) {
+                               case ERROR_FILE_NOT_FOUND:      // The device was disconnected
+                                       return LIBUSB_ERROR_NO_DEVICE;
+                               case ERROR_ACCESS_DENIED:
+                                       return LIBUSB_ERROR_ACCESS;
+                               default:
+                                       return LIBUSB_ERROR_IO;
+                               }
+                       }
+                       handle_priv->interface_handle[i].dev_handle = file_handle;
+               }
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE file_handle;
+       int i;
+
+       if (sub_api == SUB_API_NOTSET)
+               sub_api = priv->sub_api;
+       if (!WinUSBX[sub_api].initialized)
+               return;
+
+       for (i = 0; i < USB_MAXINTERFACES; i++) {
+               if (priv->usb_interface[i].apib->id == USB_API_WINUSBX) {
+                       file_handle = handle_priv->interface_handle[i].dev_handle;
+                       if ( (file_handle != 0) && (file_handle != INVALID_HANDLE_VALUE)) {
+                               CloseHandle(file_handle);
+                       }
+               }
+       }
+}
+
+static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE winusb_handle = handle_priv->interface_handle[iface].api_handle;
+       UCHAR policy;
+       ULONG timeout = 0;
+       uint8_t endpoint_address;
+       int i;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       // With handle and enpoints set (in parent), we can setup the default pipe properties
+       // see http://download.microsoft.com/download/D/1/D/D1DD7745-426B-4CC3-A269-ABBBE427C0EF/DVC-T705_DDC08.pptx
+       for (i=-1; i<priv->usb_interface[iface].nb_endpoints; i++) {
+               endpoint_address =(i==-1)?0:priv->usb_interface[iface].endpoint[i];
+               if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
+                       PIPE_TRANSFER_TIMEOUT, sizeof(ULONG), &timeout)) {
+                       usbi_dbg("failed to set PIPE_TRANSFER_TIMEOUT for control endpoint %02X", endpoint_address);
+               }
+               if ((i == -1) || (sub_api == SUB_API_LIBUSB0)) {
+                       continue;       // Other policies don't apply to control endpoint or libusb0
+               }
+               policy = false;
+               if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
+                       SHORT_PACKET_TERMINATE, sizeof(UCHAR), &policy)) {
+                       usbi_dbg("failed to disable SHORT_PACKET_TERMINATE for endpoint %02X", endpoint_address);
+               }
+               if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
+                       IGNORE_SHORT_PACKETS, sizeof(UCHAR), &policy)) {
+                       usbi_dbg("failed to disable IGNORE_SHORT_PACKETS for endpoint %02X", endpoint_address);
+               }
+               policy = true;
+               /* ALLOW_PARTIAL_READS must be enabled due to likely libusbK bug. See:
+                  https://sourceforge.net/mailarchive/message.php?msg_id=29736015 */
+               if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
+                       ALLOW_PARTIAL_READS, sizeof(UCHAR), &policy)) {
+                       usbi_dbg("failed to enable ALLOW_PARTIAL_READS for endpoint %02X", endpoint_address);
+               }
+               if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
+                       AUTO_CLEAR_STALL, sizeof(UCHAR), &policy)) {
+                       usbi_dbg("failed to enable AUTO_CLEAR_STALL for endpoint %02X", endpoint_address);
+               }
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       bool is_using_usbccgp = (priv->apib->id == USB_API_COMPOSITE);
+       HANDLE file_handle, winusb_handle;
+       DWORD err;
+       int i;
+       SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
+       HDEVINFO dev_info = INVALID_HANDLE_VALUE;
+       SP_DEVINFO_DATA dev_info_data;
+       char* dev_path_no_guid = NULL;
+       char filter_path[] = "\\\\.\\libusb0-0000";
+       bool found_filter = false;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       // If the device is composite, but using the default Windows composite parent driver (usbccgp)
+       // or if it's the first WinUSB-like interface, we get a handle through Initialize().
+       if ((is_using_usbccgp) || (iface == 0)) {
+               // composite device (independent interfaces) or interface 0
+               file_handle = handle_priv->interface_handle[iface].dev_handle;
+               if ((file_handle == 0) || (file_handle == INVALID_HANDLE_VALUE)) {
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+
+               if (!WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
+                       handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
+                       err = GetLastError();
+                       switch(err) {
+                       case ERROR_BAD_COMMAND:
+                               // The device was disconnected
+                               usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(0));
+                               return LIBUSB_ERROR_NO_DEVICE;
+                       default:
+                               // it may be that we're using the libusb0 filter driver.
+                               // TODO: can we move this whole business into the K/0 DLL?
+                               for (i = 0; ; i++) {
+                                       safe_free(dev_interface_details);
+                                       safe_free(dev_path_no_guid);
+                                       dev_interface_details = get_interface_details_filter(ctx, &dev_info, &dev_info_data, &GUID_DEVINTERFACE_LIBUSB0_FILTER, i, filter_path);
+                                       if ((found_filter) || (dev_interface_details == NULL)) {
+                                               break;
+                                       }
+                                       // ignore GUID part
+                                       dev_path_no_guid = sanitize_path(strtok(dev_interface_details->DevicePath, "{"));
+                                       if (safe_strncmp(dev_path_no_guid, priv->usb_interface[iface].path, safe_strlen(dev_path_no_guid)) == 0) {
+                                               file_handle = CreateFileA(filter_path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
+                                                       NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
+                                               if (file_handle == INVALID_HANDLE_VALUE) {
+                                                       usbi_err(ctx, "could not open device %s: %s", filter_path, windows_error_str(0));
+                                               } else {
+                                                       WinUSBX[sub_api].Free(winusb_handle);
+                                                       if (!WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
+                                                               continue;
+                                                       }
+                                                       found_filter = true;
+                                                       break;
+                                               }
+                                       }
+                               }
+                               if (!found_filter) {
+                                       usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(err));
+                                       return LIBUSB_ERROR_ACCESS;
+                               }
+                       }
+               }
+               handle_priv->interface_handle[iface].api_handle = winusb_handle;
+       } else {
+               // For all other interfaces, use GetAssociatedInterface()
+               winusb_handle = handle_priv->interface_handle[0].api_handle;
+               // It is a requirement for multiple interface devices on Windows that, to you
+               // must first claim the first interface before you claim the others
+               if ((winusb_handle == 0) || (winusb_handle == INVALID_HANDLE_VALUE)) {
+                       file_handle = handle_priv->interface_handle[0].dev_handle;
+                       if (WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
+                               handle_priv->interface_handle[0].api_handle = winusb_handle;
+                               usbi_warn(ctx, "auto-claimed interface 0 (required to claim %d with WinUSB)", iface);
+                       } else {
+                               usbi_warn(ctx, "failed to auto-claim interface 0 (required to claim %d with WinUSB): %s", iface, windows_error_str(0));
+                               return LIBUSB_ERROR_ACCESS;
+                       }
+               }
+               if (!WinUSBX[sub_api].GetAssociatedInterface(winusb_handle, (UCHAR)(iface-1),
+                       &handle_priv->interface_handle[iface].api_handle)) {
+                       handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
+                       switch(GetLastError()) {
+                       case ERROR_NO_MORE_ITEMS:   // invalid iface
+                               return LIBUSB_ERROR_NOT_FOUND;
+                       case ERROR_BAD_COMMAND:     // The device was disconnected
+                               return LIBUSB_ERROR_NO_DEVICE;
+                       case ERROR_ALREADY_EXISTS:  // already claimed
+                               return LIBUSB_ERROR_BUSY;
+                       default:
+                               usbi_err(ctx, "could not claim interface %d: %s", iface, windows_error_str(0));
+                               return LIBUSB_ERROR_ACCESS;
+                       }
+               }
+       }
+       usbi_dbg("claimed interface %d", iface);
+       handle_priv->active_interface = iface;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE winusb_handle;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       winusb_handle = handle_priv->interface_handle[iface].api_handle;
+       if ((winusb_handle == 0) || (winusb_handle == INVALID_HANDLE_VALUE)) {
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       WinUSBX[sub_api].Free(winusb_handle);
+       handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
+
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * Return the first valid interface (of the same API type), for control transfers
+ */
+static int get_valid_interface(struct libusb_device_handle *dev_handle, int api_id)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       int i;
+
+       if ((api_id < USB_API_WINUSBX) || (api_id > USB_API_HID)) {
+               usbi_dbg("unsupported API ID");
+               return -1;
+       }
+
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               if ( (handle_priv->interface_handle[i].dev_handle != 0)
+                 && (handle_priv->interface_handle[i].dev_handle != INVALID_HANDLE_VALUE)
+                 && (handle_priv->interface_handle[i].api_handle != 0)
+                 && (handle_priv->interface_handle[i].api_handle != INVALID_HANDLE_VALUE)
+                 && (priv->usb_interface[i].apib->id == api_id) ) {
+                       return i;
+               }
+       }
+       return -1;
+}
+
+/*
+ * Lookup interface by endpoint address. -1 if not found
+ */
+static int interface_by_endpoint(struct windows_device_priv *priv,
+       struct windows_device_handle_priv *handle_priv, uint8_t endpoint_address)
+{
+       int i, j;
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               if (handle_priv->interface_handle[i].api_handle == INVALID_HANDLE_VALUE)
+                       continue;
+               if (handle_priv->interface_handle[i].api_handle == 0)
+                       continue;
+               if (priv->usb_interface[i].endpoint == NULL)
+                       continue;
+               for (j=0; j<priv->usb_interface[i].nb_endpoints; j++) {
+                       if (priv->usb_interface[i].endpoint[j] == endpoint_address) {
+                               return i;
+                       }
+               }
+       }
+       return -1;
+}
+
+static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(
+               transfer->dev_handle);
+       WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *) transfer->buffer;
+       ULONG size;
+       HANDLE winusb_handle;
+       int current_interface;
+       struct winfd wfd;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       transfer_priv->pollable_fd = INVALID_WINFD;
+       size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;
+
+       if (size > MAX_CTRL_BUFFER_LENGTH)
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       current_interface = get_valid_interface(transfer->dev_handle, USB_API_WINUSBX);
+       if (current_interface < 0) {
+               if (auto_claim(transfer, &current_interface, USB_API_WINUSBX) != LIBUSB_SUCCESS) {
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+       }
+
+       usbi_dbg("will use interface %d", current_interface);
+       winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
+
+       wfd = usbi_create_fd(winusb_handle, RW_READ, NULL, NULL);
+       // Always use the handle returned from usbi_create_fd (wfd.handle)
+       if (wfd.fd < 0) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       // Sending of set configuration control requests from WinUSB creates issues
+       if ( ((setup->request_type & (0x03 << 5)) == LIBUSB_REQUEST_TYPE_STANDARD)
+         && (setup->request == LIBUSB_REQUEST_SET_CONFIGURATION) ) {
+               if (setup->value != priv->active_config) {
+                       usbi_warn(ctx, "cannot set configuration other than the default one");
+                       usbi_free_fd(&wfd);
+                       return LIBUSB_ERROR_INVALID_PARAM;
+               }
+               wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
+               wfd.overlapped->InternalHigh = 0;
+       } else {
+               if (!WinUSBX[sub_api].ControlTransfer(wfd.handle, *setup, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, size, NULL, wfd.overlapped)) {
+                       if(GetLastError() != ERROR_IO_PENDING) {
+                               usbi_warn(ctx, "ControlTransfer failed: %s", windows_error_str(0));
+                               usbi_free_fd(&wfd);
+                               return LIBUSB_ERROR_IO;
+                       }
+               } else {
+                       wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
+                       wfd.overlapped->InternalHigh = (DWORD)size;
+               }
+       }
+
+       // Use priv_transfer to store data needed for async polling
+       transfer_priv->pollable_fd = wfd;
+       transfer_priv->interface_number = (uint8_t)current_interface;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE winusb_handle;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       if (altsetting > 255) {
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       winusb_handle = handle_priv->interface_handle[iface].api_handle;
+       if ((winusb_handle == 0) || (winusb_handle == INVALID_HANDLE_VALUE)) {
+               usbi_err(ctx, "interface must be claimed first");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       if (!WinUSBX[sub_api].SetCurrentAlternateSetting(winusb_handle, (UCHAR)altsetting)) {
+               usbi_err(ctx, "SetCurrentAlternateSetting failed: %s", windows_error_str(0));
+               return LIBUSB_ERROR_IO;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       HANDLE winusb_handle;
+       bool ret;
+       int current_interface;
+       struct winfd wfd;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       transfer_priv->pollable_fd = INVALID_WINFD;
+
+       current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);
+
+       winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
+
+       wfd = usbi_create_fd(winusb_handle, IS_XFERIN(transfer) ? RW_READ : RW_WRITE, NULL, NULL);
+       // Always use the handle returned from usbi_create_fd (wfd.handle)
+       if (wfd.fd < 0) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       if (IS_XFERIN(transfer)) {
+               usbi_dbg("reading %d bytes", transfer->length);
+               ret = WinUSBX[sub_api].ReadPipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
+       } else {
+               usbi_dbg("writing %d bytes", transfer->length);
+               ret = WinUSBX[sub_api].WritePipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
+       }
+       if (!ret) {
+               if(GetLastError() != ERROR_IO_PENDING) {
+                       usbi_err(ctx, "ReadPipe/WritePipe failed: %s", windows_error_str(0));
+                       usbi_free_fd(&wfd);
+                       return LIBUSB_ERROR_IO;
+               }
+       } else {
+               wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
+               wfd.overlapped->InternalHigh = (DWORD)transfer->length;
+       }
+
+       transfer_priv->pollable_fd = wfd;
+       transfer_priv->interface_number = (uint8_t)current_interface;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE winusb_handle;
+       int current_interface;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
+       winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
+
+       if (!WinUSBX[sub_api].ResetPipe(winusb_handle, endpoint)) {
+               usbi_err(ctx, "ResetPipe failed: %s", windows_error_str(0));
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * from http://www.winvistatips.com/winusb-bugchecks-t335323.html (confirmed
+ * through testing as well):
+ * "You can not call WinUsb_AbortPipe on control pipe. You can possibly cancel
+ * the control transfer using CancelIo"
+ */
+static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer)
+{
+       // Cancelling of the I/O is done in the parent
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       HANDLE winusb_handle;
+       int current_interface;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       current_interface = transfer_priv->interface_number;
+       if ((current_interface < 0) || (current_interface >= USB_MAXINTERFACES)) {
+               usbi_err(ctx, "program assertion failed: invalid interface_number");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+       usbi_dbg("will use interface %d", current_interface);
+
+       winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
+
+       if (!WinUSBX[sub_api].AbortPipe(winusb_handle, transfer->endpoint)) {
+               usbi_err(ctx, "AbortPipe failed: %s", windows_error_str(0));
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+/*
+ * from the "How to Use WinUSB to Communicate with a USB Device" Microsoft white paper
+ * (http://www.microsoft.com/whdc/connect/usb/winusb_howto.mspx):
+ * "WinUSB does not support host-initiated reset port and cycle port operations" and
+ * IOCTL_INTERNAL_USB_CYCLE_PORT is only available in kernel mode and the
+ * IOCTL_USB_HUB_CYCLE_PORT ioctl was removed from Vista => the best we can do is
+ * cycle the pipes (and even then, the control pipe can not be reset using WinUSB)
+ */
+// TODO: (post hotplug): see if we can force eject the device and redetect it (reuse hotplug?)
+static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct winfd wfd;
+       HANDLE winusb_handle;
+       int i, j;
+
+       CHECK_WINUSBX_AVAILABLE(sub_api);
+
+       // Reset any available pipe (except control)
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               winusb_handle = handle_priv->interface_handle[i].api_handle;
+               for (wfd = handle_to_winfd(winusb_handle); wfd.fd > 0;)
+               {
+                       // Cancel any pollable I/O
+                       usbi_remove_pollfd(ctx, wfd.fd);
+                       usbi_free_fd(&wfd);
+                       wfd = handle_to_winfd(winusb_handle);
+               }
+
+               if ( (winusb_handle != 0) && (winusb_handle != INVALID_HANDLE_VALUE)) {
+                       for (j=0; j<priv->usb_interface[i].nb_endpoints; j++) {
+                               usbi_dbg("resetting ep %02X", priv->usb_interface[i].endpoint[j]);
+                               if (!WinUSBX[sub_api].AbortPipe(winusb_handle, priv->usb_interface[i].endpoint[j])) {
+                                       usbi_err(ctx, "AbortPipe (pipe address %02X) failed: %s",
+                                               priv->usb_interface[i].endpoint[j], windows_error_str(0));
+                               }
+                               // FlushPipe seems to fail on OUT pipes
+                               if (IS_EPIN(priv->usb_interface[i].endpoint[j])
+                                 && (!WinUSBX[sub_api].FlushPipe(winusb_handle, priv->usb_interface[i].endpoint[j])) ) {
+                                       usbi_err(ctx, "FlushPipe (pipe address %02X) failed: %s",
+                                               priv->usb_interface[i].endpoint[j], windows_error_str(0));
+                               }
+                               if (!WinUSBX[sub_api].ResetPipe(winusb_handle, priv->usb_interface[i].endpoint[j])) {
+                                       usbi_err(ctx, "ResetPipe (pipe address %02X) failed: %s",
+                                               priv->usb_interface[i].endpoint[j], windows_error_str(0));
+                               }
+                       }
+               }
+       }
+
+       // libusbK & libusb0 have the ability to issue an actual device reset
+       if (WinUSBX[sub_api].ResetDevice != NULL) {
+               winusb_handle = handle_priv->interface_handle[0].api_handle;
+               if ( (winusb_handle != 0) && (winusb_handle != INVALID_HANDLE_VALUE)) {
+                       WinUSBX[sub_api].ResetDevice(winusb_handle);
+               }
+       }
+       return LIBUSB_SUCCESS;
+}
+
+static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
+{
+       itransfer->transferred += io_size;
+       return LIBUSB_TRANSFER_COMPLETED;
+}
+
+/*
+ * Internal HID Support functions (from libusb-win32)
+ * Note that functions that complete data transfer synchronously must return
+ * LIBUSB_COMPLETED instead of LIBUSB_SUCCESS
+ */
+static int _hid_get_hid_descriptor(struct hid_device_priv* dev, void *data, size_t *size);
+static int _hid_get_report_descriptor(struct hid_device_priv* dev, void *data, size_t *size);
+
+static int _hid_wcslen(WCHAR *str)
+{
+       int i = 0;
+       while (str[i] && (str[i] != 0x409)) {
+               i++;
+       }
+       return i;
+}
+
+static int _hid_get_device_descriptor(struct hid_device_priv* dev, void *data, size_t *size)
+{
+       struct libusb_device_descriptor d;
+
+       d.bLength = LIBUSB_DT_DEVICE_SIZE;
+       d.bDescriptorType = LIBUSB_DT_DEVICE;
+       d.bcdUSB = 0x0200; /* 2.00 */
+       d.bDeviceClass = 0;
+       d.bDeviceSubClass = 0;
+       d.bDeviceProtocol = 0;
+       d.bMaxPacketSize0 = 64; /* fix this! */
+       d.idVendor = (uint16_t)dev->vid;
+       d.idProduct = (uint16_t)dev->pid;
+       d.bcdDevice = 0x0100;
+       d.iManufacturer = dev->string_index[0];
+       d.iProduct = dev->string_index[1];
+       d.iSerialNumber = dev->string_index[2];
+       d.bNumConfigurations = 1;
+
+       if (*size > LIBUSB_DT_DEVICE_SIZE)
+               *size = LIBUSB_DT_DEVICE_SIZE;
+       memcpy(data, &d, *size);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_get_config_descriptor(struct hid_device_priv* dev, void *data, size_t *size)
+{
+       char num_endpoints = 0;
+       size_t config_total_len = 0;
+       char tmp[HID_MAX_CONFIG_DESC_SIZE];
+       struct libusb_config_descriptor *cd;
+       struct libusb_interface_descriptor *id;
+       struct libusb_hid_descriptor *hd;
+       struct libusb_endpoint_descriptor *ed;
+       size_t tmp_size;
+
+       if (dev->input_report_size)
+               num_endpoints++;
+       if (dev->output_report_size)
+               num_endpoints++;
+
+       config_total_len = LIBUSB_DT_CONFIG_SIZE + LIBUSB_DT_INTERFACE_SIZE
+               + LIBUSB_DT_HID_SIZE + num_endpoints * LIBUSB_DT_ENDPOINT_SIZE;
+
+
+       cd = (struct libusb_config_descriptor *)tmp;
+       id = (struct libusb_interface_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE);
+       hd = (struct libusb_hid_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
+               + LIBUSB_DT_INTERFACE_SIZE);
+       ed = (struct libusb_endpoint_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
+               + LIBUSB_DT_INTERFACE_SIZE
+               + LIBUSB_DT_HID_SIZE);
+
+       cd->bLength = LIBUSB_DT_CONFIG_SIZE;
+       cd->bDescriptorType = LIBUSB_DT_CONFIG;
+       cd->wTotalLength = (uint16_t) config_total_len;
+       cd->bNumInterfaces = 1;
+       cd->bConfigurationValue = 1;
+       cd->iConfiguration = 0;
+       cd->bmAttributes = 1 << 7; /* bus powered */
+       cd->MaxPower = 50;
+
+       id->bLength = LIBUSB_DT_INTERFACE_SIZE;
+       id->bDescriptorType = LIBUSB_DT_INTERFACE;
+       id->bInterfaceNumber = 0;
+       id->bAlternateSetting = 0;
+       id->bNumEndpoints = num_endpoints;
+       id->bInterfaceClass = 3;
+       id->bInterfaceSubClass = 0;
+       id->bInterfaceProtocol = 0;
+       id->iInterface = 0;
+
+       tmp_size = LIBUSB_DT_HID_SIZE;
+       _hid_get_hid_descriptor(dev, hd, &tmp_size);
+
+       if (dev->input_report_size) {
+               ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
+               ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
+               ed->bEndpointAddress = HID_IN_EP;
+               ed->bmAttributes = 3;
+               ed->wMaxPacketSize = dev->input_report_size - 1;
+               ed->bInterval = 10;
+               ed = (struct libusb_endpoint_descriptor *)((char*)ed + LIBUSB_DT_ENDPOINT_SIZE);
+       }
+
+       if (dev->output_report_size) {
+               ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
+               ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
+               ed->bEndpointAddress = HID_OUT_EP;
+               ed->bmAttributes = 3;
+               ed->wMaxPacketSize = dev->output_report_size - 1;
+               ed->bInterval = 10;
+       }
+
+       if (*size > config_total_len)
+               *size = config_total_len;
+       memcpy(data, tmp, *size);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_get_string_descriptor(struct hid_device_priv* dev, int _index,
+                                                                         void *data, size_t *size)
+{
+       void *tmp = NULL;
+       size_t tmp_size = 0;
+       int i;
+
+       /* language ID, EN-US */
+       char string_langid[] = {
+               0x09,
+               0x04
+       };
+
+       if ((*size < 2) || (*size > 255)) {
+               return LIBUSB_ERROR_OVERFLOW;
+       }
+
+       if (_index == 0) {
+               tmp = string_langid;
+               tmp_size = sizeof(string_langid)+2;
+       } else {
+               for (i=0; i<3; i++) {
+                       if (_index == (dev->string_index[i])) {
+                               tmp = dev->string[i];
+                               tmp_size = (_hid_wcslen(dev->string[i])+1) * sizeof(WCHAR);
+                               break;
+                       }
+               }
+               if (i == 3) {   // not found
+                       return LIBUSB_ERROR_INVALID_PARAM;
+               }
+       }
+
+       if(!tmp_size) {
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       if (tmp_size < *size) {
+               *size = tmp_size;
+       }
+       // 2 byte header
+       ((uint8_t*)data)[0] = (uint8_t)*size;
+       ((uint8_t*)data)[1] = LIBUSB_DT_STRING;
+       memcpy((uint8_t*)data+2, tmp, *size-2);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_get_hid_descriptor(struct hid_device_priv* dev, void *data, size_t *size)
+{
+       struct libusb_hid_descriptor d;
+       uint8_t tmp[MAX_HID_DESCRIPTOR_SIZE];
+       size_t report_len = MAX_HID_DESCRIPTOR_SIZE;
+
+       _hid_get_report_descriptor(dev, tmp, &report_len);
+
+       d.bLength = LIBUSB_DT_HID_SIZE;
+       d.bDescriptorType = LIBUSB_DT_HID;
+       d.bcdHID = 0x0110; /* 1.10 */
+       d.bCountryCode = 0;
+       d.bNumDescriptors = 1;
+       d.bClassDescriptorType = LIBUSB_DT_REPORT;
+       d.wClassDescriptorLength = (uint16_t)report_len;
+
+       if (*size > LIBUSB_DT_HID_SIZE)
+               *size = LIBUSB_DT_HID_SIZE;
+       memcpy(data, &d, *size);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_get_report_descriptor(struct hid_device_priv* dev, void *data, size_t *size)
+{
+       uint8_t d[MAX_HID_DESCRIPTOR_SIZE];
+       size_t i = 0;
+
+       /* usage page (0xFFA0 == vendor defined) */
+       d[i++] = 0x06; d[i++] = 0xA0; d[i++] = 0xFF;
+       /* usage (vendor defined) */
+       d[i++] = 0x09; d[i++] = 0x01;
+       /* start collection (application) */
+       d[i++] = 0xA1; d[i++] = 0x01;
+       /* input report */
+       if (dev->input_report_size) {
+               /* usage (vendor defined) */
+               d[i++] = 0x09; d[i++] = 0x01;
+               /* logical minimum (0) */
+               d[i++] = 0x15; d[i++] = 0x00;
+               /* logical maximum (255) */
+               d[i++] = 0x25; d[i++] = 0xFF;
+               /* report size (8 bits) */
+               d[i++] = 0x75; d[i++] = 0x08;
+               /* report count */
+               d[i++] = 0x95; d[i++] = (uint8_t)dev->input_report_size - 1;
+               /* input (data, variable, absolute) */
+               d[i++] = 0x81; d[i++] = 0x00;
+       }
+       /* output report */
+       if (dev->output_report_size) {
+               /* usage (vendor defined) */
+               d[i++] = 0x09; d[i++] = 0x02;
+               /* logical minimum (0) */
+               d[i++] = 0x15; d[i++] = 0x00;
+               /* logical maximum (255) */
+               d[i++] = 0x25; d[i++] = 0xFF;
+               /* report size (8 bits) */
+               d[i++] = 0x75; d[i++] = 0x08;
+               /* report count */
+               d[i++] = 0x95; d[i++] = (uint8_t)dev->output_report_size - 1;
+               /* output (data, variable, absolute) */
+               d[i++] = 0x91; d[i++] = 0x00;
+       }
+       /* feature report */
+       if (dev->feature_report_size) {
+               /* usage (vendor defined) */
+               d[i++] = 0x09; d[i++] = 0x03;
+               /* logical minimum (0) */
+               d[i++] = 0x15; d[i++] = 0x00;
+               /* logical maximum (255) */
+               d[i++] = 0x25; d[i++] = 0xFF;
+               /* report size (8 bits) */
+               d[i++] = 0x75; d[i++] = 0x08;
+               /* report count */
+               d[i++] = 0x95; d[i++] = (uint8_t)dev->feature_report_size - 1;
+               /* feature (data, variable, absolute) */
+               d[i++] = 0xb2; d[i++] = 0x02; d[i++] = 0x01;
+       }
+
+       /* end collection */
+       d[i++] = 0xC0;
+
+       if (*size > i)
+               *size = i;
+       memcpy(data, d, *size);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_get_descriptor(struct hid_device_priv* dev, HANDLE hid_handle, int recipient,
+                                                          int type, int _index, void *data, size_t *size)
+{
+       switch(type) {
+       case LIBUSB_DT_DEVICE:
+               usbi_dbg("LIBUSB_DT_DEVICE");
+               return _hid_get_device_descriptor(dev, data, size);
+       case LIBUSB_DT_CONFIG:
+               usbi_dbg("LIBUSB_DT_CONFIG");
+               if (!_index)
+                       return _hid_get_config_descriptor(dev, data, size);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       case LIBUSB_DT_STRING:
+               usbi_dbg("LIBUSB_DT_STRING");
+               return _hid_get_string_descriptor(dev, _index, data, size);
+       case LIBUSB_DT_HID:
+               usbi_dbg("LIBUSB_DT_HID");
+               if (!_index)
+                       return _hid_get_hid_descriptor(dev, data, size);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       case LIBUSB_DT_REPORT:
+               usbi_dbg("LIBUSB_DT_REPORT");
+               if (!_index)
+                       return _hid_get_report_descriptor(dev, data, size);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       case LIBUSB_DT_PHYSICAL:
+               usbi_dbg("LIBUSB_DT_PHYSICAL");
+               if (HidD_GetPhysicalDescriptor(hid_handle, data, (ULONG)*size))
+                       return LIBUSB_COMPLETED;
+               return LIBUSB_ERROR_OTHER;
+       }
+       usbi_dbg("unsupported");
+       return LIBUSB_ERROR_INVALID_PARAM;
+}
+
+static int _hid_get_report(struct hid_device_priv* dev, HANDLE hid_handle, int id, void *data,
+                                                  struct windows_transfer_priv *tp, size_t *size, OVERLAPPED* overlapped,
+                                                  int report_type)
+{
+       uint8_t *buf;
+       DWORD ioctl_code, read_size, expected_size = (DWORD)*size;
+       int r = LIBUSB_SUCCESS;
+
+       if (tp->hid_buffer != NULL) {
+               usbi_dbg("program assertion failed: hid_buffer is not NULL");
+       }
+
+       if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
+               usbi_dbg("invalid size (%d)", *size);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       switch (report_type) {
+               case HID_REPORT_TYPE_INPUT:
+                       ioctl_code = IOCTL_HID_GET_INPUT_REPORT;
+                       break;
+               case HID_REPORT_TYPE_FEATURE:
+                       ioctl_code = IOCTL_HID_GET_FEATURE;
+                       break;
+               default:
+                       usbi_dbg("unknown HID report type %d", report_type);
+                       return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       // Add a trailing byte to detect overflows
+       buf = (uint8_t*)calloc(expected_size+1, 1);
+       if (buf == NULL) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+       buf[0] = (uint8_t)id;   // Must be set always
+       usbi_dbg("report ID: 0x%02X", buf[0]);
+
+       tp->hid_expected_size = expected_size;
+       read_size = expected_size;
+
+       // NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
+       if (!DeviceIoControl(hid_handle, ioctl_code, buf, expected_size+1,
+               buf, expected_size+1, &read_size, overlapped)) {
+               if (GetLastError() != ERROR_IO_PENDING) {
+                       usbi_dbg("Failed to Read HID Report: %s", windows_error_str(0));
+                       safe_free(buf);
+                       return LIBUSB_ERROR_IO;
+               }
+               // Asynchronous wait
+               tp->hid_buffer = buf;
+               tp->hid_dest = (uint8_t*)data; // copy dest, as not necessarily the start of the transfer buffer
+               return LIBUSB_SUCCESS;
+       }
+
+       // Transfer completed synchronously => copy and discard extra buffer
+       if (read_size == 0) {
+               usbi_warn(NULL, "program assertion failed - read completed synchronously, but no data was read");
+               *size = 0;
+       } else {
+               if (buf[0] != id) {
+                       usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);
+               }
+               if ((size_t)read_size > expected_size) {
+                       r = LIBUSB_ERROR_OVERFLOW;
+                       usbi_dbg("OVERFLOW!");
+               } else {
+                       r = LIBUSB_COMPLETED;
+               }
+
+               *size = MIN((size_t)read_size, *size);
+               if (id == 0) {
+                       // Discard report ID
+                       memcpy(data, buf+1, *size);
+               } else {
+                       memcpy(data, buf, *size);
+               }
+       }
+       safe_free(buf);
+       return r;
+}
+
+static int _hid_set_report(struct hid_device_priv* dev, HANDLE hid_handle, int id, void *data,
+                                                  struct windows_transfer_priv *tp, size_t *size, OVERLAPPED* overlapped,
+                                                  int report_type)
+{
+       uint8_t *buf = NULL;
+       DWORD ioctl_code, write_size= (DWORD)*size;
+
+       if (tp->hid_buffer != NULL) {
+               usbi_dbg("program assertion failed: hid_buffer is not NULL");
+       }
+
+       if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
+               usbi_dbg("invalid size (%d)", *size);
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       switch (report_type) {
+               case HID_REPORT_TYPE_OUTPUT:
+                       ioctl_code = IOCTL_HID_SET_OUTPUT_REPORT;
+                       break;
+               case HID_REPORT_TYPE_FEATURE:
+                       ioctl_code = IOCTL_HID_SET_FEATURE;
+                       break;
+               default:
+                       usbi_dbg("unknown HID report type %d", report_type);
+                       return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       usbi_dbg("report ID: 0x%02X", id);
+       // When report IDs are not used (i.e. when id == 0), we must add
+       // a null report ID. Otherwise, we just use original data buffer
+       if (id == 0) {
+               write_size++;
+       }
+       buf = (uint8_t*) malloc(write_size);
+       if (buf == NULL) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+       if (id == 0) {
+               buf[0] = 0;
+               memcpy(buf + 1, data, *size);
+       } else {
+               // This seems like a waste, but if we don't duplicate the
+               // data, we'll get issues when freeing hid_buffer
+               memcpy(buf, data, *size);
+               if (buf[0] != id) {
+                       usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);
+               }
+       }
+
+       // NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
+       if (!DeviceIoControl(hid_handle, ioctl_code, buf, write_size,
+               buf, write_size, &write_size, overlapped)) {
+               if (GetLastError() != ERROR_IO_PENDING) {
+                       usbi_dbg("Failed to Write HID Output Report: %s", windows_error_str(0));
+                       safe_free(buf);
+                       return LIBUSB_ERROR_IO;
+               }
+               tp->hid_buffer = buf;
+               tp->hid_dest = NULL;
+               return LIBUSB_SUCCESS;
+       }
+
+       // Transfer completed synchronously
+       *size = write_size;
+       if (write_size == 0) {
+               usbi_dbg("program assertion failed - write completed synchronously, but no data was written");
+       }
+       safe_free(buf);
+       return LIBUSB_COMPLETED;
+}
+
+static int _hid_class_request(struct hid_device_priv* dev, HANDLE hid_handle, int request_type,
+                                                         int request, int value, int _index, void *data, struct windows_transfer_priv *tp,
+                                                         size_t *size, OVERLAPPED* overlapped)
+{
+       int report_type = (value >> 8) & 0xFF;
+       int report_id = value & 0xFF;
+
+       if ( (LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_INTERFACE)
+         && (LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_DEVICE) )
+               return LIBUSB_ERROR_INVALID_PARAM;
+
+       if (LIBUSB_REQ_OUT(request_type) && request == HID_REQ_SET_REPORT)
+               return _hid_set_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);
+
+       if (LIBUSB_REQ_IN(request_type) && request == HID_REQ_GET_REPORT)
+               return _hid_get_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);
+
+       return LIBUSB_ERROR_INVALID_PARAM;
+}
+
+
+/*
+ * HID API functions
+ */
+static int hid_init(int sub_api, struct libusb_context *ctx)
+{
+       DLL_LOAD(hid.dll, HidD_GetAttributes, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetHidGuid, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetPreparsedData, TRUE);
+       DLL_LOAD(hid.dll, HidD_FreePreparsedData, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetManufacturerString, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetProductString, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetSerialNumberString, TRUE);
+       DLL_LOAD(hid.dll, HidP_GetCaps, TRUE);
+       DLL_LOAD(hid.dll, HidD_SetNumInputBuffers, TRUE);
+       DLL_LOAD(hid.dll, HidD_SetFeature, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetFeature, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetPhysicalDescriptor, TRUE);
+       DLL_LOAD(hid.dll, HidD_GetInputReport, FALSE);
+       DLL_LOAD(hid.dll, HidD_SetOutputReport, FALSE);
+       DLL_LOAD(hid.dll, HidD_FlushQueue, TRUE);
+       DLL_LOAD(hid.dll, HidP_GetValueCaps, TRUE);
+
+       api_hid_available = true;
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_exit(int sub_api)
+{
+       return LIBUSB_SUCCESS;
+}
+
+// NB: open and close must ensure that they only handle interface of
+// the right API type, as these functions can be called wholesale from
+// composite_open(), with interfaces belonging to different APIs
+static int hid_open(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+
+       HIDD_ATTRIBUTES hid_attributes;
+       PHIDP_PREPARSED_DATA preparsed_data = NULL;
+       HIDP_CAPS capabilities;
+       HIDP_VALUE_CAPS *value_caps;
+
+       HANDLE hid_handle = INVALID_HANDLE_VALUE;
+       int i, j;
+       // report IDs handling
+       ULONG size[3];
+       const char* type[3] = {"input", "output", "feature"};
+       int nb_ids[2];  // zero and nonzero report IDs
+
+       CHECK_HID_AVAILABLE;
+       if (priv->hid == NULL) {
+               usbi_err(ctx, "program assertion failed - private HID structure is unitialized");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       for (i = 0; i < USB_MAXINTERFACES; i++) {
+               if ( (priv->usb_interface[i].path != NULL)
+                 && (priv->usb_interface[i].apib->id == USB_API_HID) ) {
+                       hid_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
+                               NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
+                       /*
+                        * http://www.lvr.com/hidfaq.htm: Why do I receive "Access denied" when attempting to access my HID?
+                        * "Windows 2000 and later have exclusive read/write access to HIDs that are configured as a system
+                        * keyboards or mice. An application can obtain a handle to a system keyboard or mouse by not
+                        * requesting READ or WRITE access with CreateFile. Applications can then use HidD_SetFeature and
+                        * HidD_GetFeature (if the device supports Feature reports)."
+                        */
+                       if (hid_handle == INVALID_HANDLE_VALUE) {
+                               usbi_warn(ctx, "could not open HID device in R/W mode (keyboard or mouse?) - trying without");
+                               hid_handle = CreateFileA(priv->usb_interface[i].path, 0, FILE_SHARE_WRITE | FILE_SHARE_READ,
+                                       NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
+                               if (hid_handle == INVALID_HANDLE_VALUE) {
+                                       usbi_err(ctx, "could not open device %s (interface %d): %s", priv->path, i, windows_error_str(0));
+                                       switch(GetLastError()) {
+                                       case ERROR_FILE_NOT_FOUND:      // The device was disconnected
+                                               return LIBUSB_ERROR_NO_DEVICE;
+                                       case ERROR_ACCESS_DENIED:
+                                               return LIBUSB_ERROR_ACCESS;
+                                       default:
+                                               return LIBUSB_ERROR_IO;
+                                       }
+                               }
+                               priv->usb_interface[i].restricted_functionality = true;
+                       }
+                       handle_priv->interface_handle[i].api_handle = hid_handle;
+               }
+       }
+
+       hid_attributes.Size = sizeof(hid_attributes);
+       do {
+               if (!HidD_GetAttributes(hid_handle, &hid_attributes)) {
+                       usbi_err(ctx, "could not gain access to HID top collection (HidD_GetAttributes)");
+                       break;
+               }
+
+               priv->hid->vid = hid_attributes.VendorID;
+               priv->hid->pid = hid_attributes.ProductID;
+
+               // Set the maximum available input buffer size
+               for (i=32; HidD_SetNumInputBuffers(hid_handle, i); i*=2);
+               usbi_dbg("set maximum input buffer size to %d", i/2);
+
+               // Get the maximum input and output report size
+               if (!HidD_GetPreparsedData(hid_handle, &preparsed_data) || !preparsed_data) {
+                       usbi_err(ctx, "could not read HID preparsed data (HidD_GetPreparsedData)");
+                       break;
+               }
+               if (HidP_GetCaps(preparsed_data, &capabilities) != HIDP_STATUS_SUCCESS) {
+                       usbi_err(ctx, "could not parse HID capabilities (HidP_GetCaps)");
+                       break;
+               }
+
+               // Find out if interrupt will need report IDs
+               size[0] = capabilities.NumberInputValueCaps;
+               size[1] = capabilities.NumberOutputValueCaps;
+               size[2] = capabilities.NumberFeatureValueCaps;
+               for (j=HidP_Input; j<=HidP_Feature; j++) {
+                       usbi_dbg("%d HID %s report value(s) found", size[j], type[j]);
+                       priv->hid->uses_report_ids[j] = false;
+                       if (size[j] > 0) {
+                               value_caps = (HIDP_VALUE_CAPS*) calloc(size[j], sizeof(HIDP_VALUE_CAPS));
+                               if ( (value_caps != NULL)
+                                 && (HidP_GetValueCaps((HIDP_REPORT_TYPE)j, value_caps, &size[j], preparsed_data) == HIDP_STATUS_SUCCESS)
+                                 && (size[j] >= 1) ) {
+                                       nb_ids[0] = 0;
+                                       nb_ids[1] = 0;
+                                       for (i=0; i<(int)size[j]; i++) {
+                                               usbi_dbg("  Report ID: 0x%02X", value_caps[i].ReportID);
+                                               if (value_caps[i].ReportID != 0) {
+                                                       nb_ids[1]++;
+                                               } else {
+                                                       nb_ids[0]++;
+                                               }
+                                       }
+                                       if (nb_ids[1] != 0) {
+                                               if (nb_ids[0] != 0) {
+                                                       usbi_warn(ctx, "program assertion failed: zero and nonzero report IDs used for %s",
+                                                               type[j]);
+                                               }
+                                               priv->hid->uses_report_ids[j] = true;
+                                       }
+                               } else {
+                                       usbi_warn(ctx, "  could not process %s report IDs", type[j]);
+                               }
+                               safe_free(value_caps);
+                       }
+               }
+
+               // Set the report sizes
+               priv->hid->input_report_size = capabilities.InputReportByteLength;
+               priv->hid->output_report_size = capabilities.OutputReportByteLength;
+               priv->hid->feature_report_size = capabilities.FeatureReportByteLength;
+
+               // Fetch string descriptors
+               priv->hid->string_index[0] = priv->dev_descriptor.iManufacturer;
+               if (priv->hid->string_index[0] != 0) {
+                       HidD_GetManufacturerString(hid_handle, priv->hid->string[0],
+                               sizeof(priv->hid->string[0]));
+               } else {
+                       priv->hid->string[0][0] = 0;
+               }
+               priv->hid->string_index[1] = priv->dev_descriptor.iProduct;
+               if (priv->hid->string_index[1] != 0) {
+                       HidD_GetProductString(hid_handle, priv->hid->string[1],
+                               sizeof(priv->hid->string[1]));
+               } else {
+                       priv->hid->string[1][0] = 0;
+               }
+               priv->hid->string_index[2] = priv->dev_descriptor.iSerialNumber;
+               if (priv->hid->string_index[2] != 0) {
+                       HidD_GetSerialNumberString(hid_handle, priv->hid->string[2],
+                               sizeof(priv->hid->string[2]));
+               } else {
+                       priv->hid->string[2][0] = 0;
+               }
+       } while(0);
+
+       if (preparsed_data) {
+               HidD_FreePreparsedData(preparsed_data);
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static void hid_close(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       HANDLE file_handle;
+       int i;
+
+       if (!api_hid_available)
+               return;
+
+       for (i = 0; i < USB_MAXINTERFACES; i++) {
+               if (priv->usb_interface[i].apib->id == USB_API_HID) {
+                       file_handle = handle_priv->interface_handle[i].api_handle;
+                       if ( (file_handle != 0) && (file_handle != INVALID_HANDLE_VALUE)) {
+                               CloseHandle(file_handle);
+                       }
+               }
+       }
+}
+
+static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       CHECK_HID_AVAILABLE;
+
+       // NB: Disconnection detection is not possible in this function
+       if (priv->usb_interface[iface].path == NULL) {
+               return LIBUSB_ERROR_NOT_FOUND;  // invalid iface
+       }
+
+       // We use dev_handle as a flag for interface claimed
+       if (handle_priv->interface_handle[iface].dev_handle == INTERFACE_CLAIMED) {
+               return LIBUSB_ERROR_BUSY;       // already claimed
+       }
+
+       handle_priv->interface_handle[iface].dev_handle = INTERFACE_CLAIMED;
+
+       usbi_dbg("claimed interface %d", iface);
+       handle_priv->active_interface = iface;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+
+       CHECK_HID_AVAILABLE;
+
+       if (priv->usb_interface[iface].path == NULL) {
+               return LIBUSB_ERROR_NOT_FOUND;  // invalid iface
+       }
+
+       if (handle_priv->interface_handle[iface].dev_handle != INTERFACE_CLAIMED) {
+               return LIBUSB_ERROR_NOT_FOUND;  // invalid iface
+       }
+
+       handle_priv->interface_handle[iface].dev_handle = INVALID_HANDLE_VALUE;
+
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+
+       CHECK_HID_AVAILABLE;
+
+       if (altsetting > 255) {
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       if (altsetting != 0) {
+               usbi_err(ctx, "set interface altsetting not supported for altsetting >0");
+               return LIBUSB_ERROR_NOT_SUPPORTED;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *) transfer->buffer;
+       HANDLE hid_handle;
+       struct winfd wfd;
+       int current_interface, config;
+       size_t size;
+       int r = LIBUSB_ERROR_INVALID_PARAM;
+
+       CHECK_HID_AVAILABLE;
+
+       transfer_priv->pollable_fd = INVALID_WINFD;
+       safe_free(transfer_priv->hid_buffer);
+       transfer_priv->hid_dest = NULL;
+       size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;
+
+       if (size > MAX_CTRL_BUFFER_LENGTH) {
+               return LIBUSB_ERROR_INVALID_PARAM;
+       }
+
+       current_interface = get_valid_interface(transfer->dev_handle, USB_API_HID);
+       if (current_interface < 0) {
+               if (auto_claim(transfer, &current_interface, USB_API_HID) != LIBUSB_SUCCESS) {
+                       return LIBUSB_ERROR_NOT_FOUND;
+               }
+       }
+
+       usbi_dbg("will use interface %d", current_interface);
+       hid_handle = handle_priv->interface_handle[current_interface].api_handle;
+       // Always use the handle returned from usbi_create_fd (wfd.handle)
+       wfd = usbi_create_fd(hid_handle, RW_READ, NULL, NULL);
+       if (wfd.fd < 0) {
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       switch(LIBUSB_REQ_TYPE(setup->request_type)) {
+       case LIBUSB_REQUEST_TYPE_STANDARD:
+               switch(setup->request) {
+               case LIBUSB_REQUEST_GET_DESCRIPTOR:
+                       r = _hid_get_descriptor(priv->hid, wfd.handle, LIBUSB_REQ_RECIPIENT(setup->request_type),
+                               (setup->value >> 8) & 0xFF, setup->value & 0xFF, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, &size);
+                       break;
+               case LIBUSB_REQUEST_GET_CONFIGURATION:
+                       r = windows_get_configuration(transfer->dev_handle, &config);
+                       if (r == LIBUSB_SUCCESS) {
+                               size = 1;
+                               ((uint8_t*)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = (uint8_t)config;
+                               r = LIBUSB_COMPLETED;
+                       }
+                       break;
+               case LIBUSB_REQUEST_SET_CONFIGURATION:
+                       if (setup->value == priv->active_config) {
+                               r = LIBUSB_COMPLETED;
+                       } else {
+                               usbi_warn(ctx, "cannot set configuration other than the default one");
+                               r = LIBUSB_ERROR_INVALID_PARAM;
+                       }
+                       break;
+               case LIBUSB_REQUEST_GET_INTERFACE:
+                       size = 1;
+                       ((uint8_t*)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = 0;
+                       r = LIBUSB_COMPLETED;
+                       break;
+               case LIBUSB_REQUEST_SET_INTERFACE:
+                       r = hid_set_interface_altsetting(0, transfer->dev_handle, setup->index, setup->value);
+                       if (r == LIBUSB_SUCCESS) {
+                               r = LIBUSB_COMPLETED;
+                       }
+                       break;
+               default:
+                       usbi_warn(ctx, "unsupported HID control request");
+                       r = LIBUSB_ERROR_INVALID_PARAM;
+                       break;
+               }
+               break;
+       case LIBUSB_REQUEST_TYPE_CLASS:
+               r =_hid_class_request(priv->hid, wfd.handle, setup->request_type, setup->request, setup->value,
+                       setup->index, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, transfer_priv,
+                       &size, wfd.overlapped);
+               break;
+       default:
+               usbi_warn(ctx, "unsupported HID control request");
+               r = LIBUSB_ERROR_INVALID_PARAM;
+               break;
+       }
+
+       if (r == LIBUSB_COMPLETED) {
+               // Force request to be completed synchronously. Transferred size has been set by previous call
+               wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
+               // http://msdn.microsoft.com/en-us/library/ms684342%28VS.85%29.aspx
+               // set InternalHigh to the number of bytes transferred
+               wfd.overlapped->InternalHigh = (DWORD)size;
+               r = LIBUSB_SUCCESS;
+       }
+
+       if (r == LIBUSB_SUCCESS) {
+               // Use priv_transfer to store data needed for async polling
+               transfer_priv->pollable_fd = wfd;
+               transfer_priv->interface_number = (uint8_t)current_interface;
+       } else {
+               usbi_free_fd(&wfd);
+       }
+
+       return r;
+}
+
+static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       struct winfd wfd;
+       HANDLE hid_handle;
+       bool direction_in, ret;
+       int current_interface, length;
+       DWORD size;
+       int r = LIBUSB_SUCCESS;
+
+       CHECK_HID_AVAILABLE;
+
+       transfer_priv->pollable_fd = INVALID_WINFD;
+       transfer_priv->hid_dest = NULL;
+       safe_free(transfer_priv->hid_buffer);
+
+       current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);
+
+       hid_handle = handle_priv->interface_handle[current_interface].api_handle;
+       direction_in = transfer->endpoint & LIBUSB_ENDPOINT_IN;
+
+       wfd = usbi_create_fd(hid_handle, direction_in?RW_READ:RW_WRITE, NULL, NULL);
+       // Always use the handle returned from usbi_create_fd (wfd.handle)
+       if (wfd.fd < 0) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+
+       // If report IDs are not in use, an extra prefix byte must be added
+       if ( ((direction_in) && (!priv->hid->uses_report_ids[0]))
+         || ((!direction_in) && (!priv->hid->uses_report_ids[1])) ) {
+               length = transfer->length+1;
+       } else {
+               length = transfer->length;
+       }
+       // Add a trailing byte to detect overflows on input
+       transfer_priv->hid_buffer = (uint8_t*)calloc(length+1, 1);
+       if (transfer_priv->hid_buffer == NULL) {
+               return LIBUSB_ERROR_NO_MEM;
+       }
+       transfer_priv->hid_expected_size = length;
+
+       if (direction_in) {
+               transfer_priv->hid_dest = transfer->buffer;
+               usbi_dbg("reading %d bytes (report ID: 0x00)", length);
+               ret = ReadFile(wfd.handle, transfer_priv->hid_buffer, length+1, &size, wfd.overlapped);
+       } else {
+               if (!priv->hid->uses_report_ids[1]) {
+                       memcpy(transfer_priv->hid_buffer+1, transfer->buffer, transfer->length);
+               } else {
+                       // We could actually do without the calloc and memcpy in this case
+                       memcpy(transfer_priv->hid_buffer, transfer->buffer, transfer->length);
+               }
+               usbi_dbg("writing %d bytes (report ID: 0x%02X)", length, transfer_priv->hid_buffer[0]);
+               ret = WriteFile(wfd.handle, transfer_priv->hid_buffer, length, &size, wfd.overlapped);
+       }
+       if (!ret) {
+               if (GetLastError() != ERROR_IO_PENDING) {
+                       usbi_err(ctx, "HID transfer failed: %s", windows_error_str(0));
+                       usbi_free_fd(&wfd);
+                       safe_free(transfer_priv->hid_buffer);
+                       return LIBUSB_ERROR_IO;
+               }
+       } else {
+               // Only write operations that completed synchronously need to free up
+               // hid_buffer. For reads, copy_transfer_data() handles that process.
+               if (!direction_in) {
+                       safe_free(transfer_priv->hid_buffer);
+               }
+               if (size == 0) {
+                       usbi_err(ctx, "program assertion failed - no data was transferred");
+                       size = 1;
+               }
+               if (size > (size_t)length) {
+                       usbi_err(ctx, "OVERFLOW!");
+                       r = LIBUSB_ERROR_OVERFLOW;
+               }
+               wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
+               wfd.overlapped->InternalHigh = size;
+       }
+
+       transfer_priv->pollable_fd = wfd;
+       transfer_priv->interface_number = (uint8_t)current_interface;
+
+       return r;
+}
+
+static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = (struct windows_transfer_priv*)usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       HANDLE hid_handle;
+       int current_interface;
+
+       CHECK_HID_AVAILABLE;
+
+       current_interface = transfer_priv->interface_number;
+       hid_handle = handle_priv->interface_handle[current_interface].api_handle;
+       CancelIo(hid_handle);
+
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       HANDLE hid_handle;
+       int current_interface;
+
+       CHECK_HID_AVAILABLE;
+
+       // Flushing the queues on all interfaces is the best we can achieve
+       for (current_interface = 0; current_interface < USB_MAXINTERFACES; current_interface++) {
+               hid_handle = handle_priv->interface_handle[current_interface].api_handle;
+               if ((hid_handle != 0) && (hid_handle != INVALID_HANDLE_VALUE)) {
+                       HidD_FlushQueue(hid_handle);
+               }
+       }
+       return LIBUSB_SUCCESS;
+}
+
+static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       HANDLE hid_handle;
+       int current_interface;
+
+       CHECK_HID_AVAILABLE;
+
+       current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
+       hid_handle = handle_priv->interface_handle[current_interface].api_handle;
+
+       // No endpoint selection with Microsoft's implementation, so we try to flush the
+       // whole interface. Should be OK for most case scenarios
+       if (!HidD_FlushQueue(hid_handle)) {
+               usbi_err(ctx, "Flushing of HID queue failed: %s", windows_error_str(0));
+               // Device was probably disconnected
+               return LIBUSB_ERROR_NO_DEVICE;
+       }
+
+       return LIBUSB_SUCCESS;
+}
+
+// This extra function is only needed for HID
+static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size) {
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
+       int r = LIBUSB_TRANSFER_COMPLETED;
+       uint32_t corrected_size = io_size;
+
+       if (transfer_priv->hid_buffer != NULL) {
+               // If we have a valid hid_buffer, it means the transfer was async
+               if (transfer_priv->hid_dest != NULL) {  // Data readout
+                       if (corrected_size > 0) {
+                               // First, check for overflow
+                               if (corrected_size > transfer_priv->hid_expected_size) {
+                                       usbi_err(ctx, "OVERFLOW!");
+                                       corrected_size = (uint32_t)transfer_priv->hid_expected_size;
+                                       r = LIBUSB_TRANSFER_OVERFLOW;
+                               }
+
+                               if (transfer_priv->hid_buffer[0] == 0) {
+                                       // Discard the 1 byte report ID prefix
+                                       corrected_size--;
+                                       memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer+1, corrected_size);
+                               } else {
+                                       memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer, corrected_size);
+                               }
+                       }
+                       transfer_priv->hid_dest = NULL;
+               }
+               // For write, we just need to free the hid buffer
+               safe_free(transfer_priv->hid_buffer);
+       }
+       itransfer->transferred += corrected_size;
+       return r;
+}
+
+
+/*
+ * Composite API functions
+ */
+static int composite_init(int sub_api, struct libusb_context *ctx)
+{
+       return LIBUSB_SUCCESS;
+}
+
+static int composite_exit(int sub_api)
+{
+       return LIBUSB_SUCCESS;
+}
+
+static int composite_open(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       int r = LIBUSB_ERROR_NOT_FOUND;
+       uint8_t i;
+       // SUB_API_MAX+1 as the SUB_API_MAX pos is used to indicate availability of HID
+       bool available[SUB_API_MAX+1] = {0};
+
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               switch (priv->usb_interface[i].apib->id) {
+               case USB_API_WINUSBX:
+                       if (priv->usb_interface[i].sub_api != SUB_API_NOTSET)
+                               available[priv->usb_interface[i].sub_api] = true;
+                       break;
+               case USB_API_HID:
+                       available[SUB_API_MAX] = true;
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       for (i=0; i<SUB_API_MAX; i++) { // WinUSB-like drivers
+               if (available[i]) {
+                       r = usb_api_backend[USB_API_WINUSBX].open(i, dev_handle);
+                       if (r != LIBUSB_SUCCESS) {
+                               return r;
+                       }
+               }
+       }
+       if (available[SUB_API_MAX]) {   // HID driver
+               r = hid_open(SUB_API_NOTSET, dev_handle);
+       }
+       return r;
+}
+
+static void composite_close(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       uint8_t i;
+       bool available[SUB_API_MAX];
+
+       for (i = 0; i<SUB_API_MAX; i++) {
+               available[i] = false;
+       }
+
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               if ( (priv->usb_interface[i].apib->id == USB_API_WINUSBX)
+                 && (priv->usb_interface[i].sub_api != SUB_API_NOTSET) ) {
+                       available[priv->usb_interface[i].sub_api] = true;
+               }
+       }
+
+       for (i=0; i<SUB_API_MAX; i++) {
+               if (available[i]) {
+                       usb_api_backend[USB_API_WINUSBX].close(i, dev_handle);
+               }
+       }
+}
+
+static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       return priv->usb_interface[iface].apib->
+               claim_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
+}
+
+static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       return priv->usb_interface[iface].apib->
+               set_interface_altsetting(priv->usb_interface[iface].sub_api, dev_handle, iface, altsetting);
+}
+
+static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       return priv->usb_interface[iface].apib->
+               release_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
+}
+
+static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int i, pass;
+
+       // Interface shouldn't matter for control, but it does in practice, with Windows'
+       // restrictions with regards to accessing HID keyboards and mice. Try a 2 pass approach
+       for (pass = 0; pass < 2; pass++) {
+               for (i=0; i<USB_MAXINTERFACES; i++) {
+                       if (priv->usb_interface[i].path != NULL) {
+                               if ((pass == 0) && (priv->usb_interface[i].restricted_functionality)) {
+                                       usbi_dbg("trying to skip restricted interface #%d (HID keyboard or mouse?)", i);
+                                       continue;
+                               }
+                               usbi_dbg("using interface %d", i);
+                               return priv->usb_interface[i].apib->submit_control_transfer(priv->usb_interface[i].sub_api, itransfer);
+                       }
+               }
+       }
+
+       usbi_err(ctx, "no libusb supported interfaces to complete request");
+       return LIBUSB_ERROR_NOT_FOUND;
+}
+
+static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int current_interface;
+
+       current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       return priv->usb_interface[current_interface].apib->
+               submit_bulk_transfer(priv->usb_interface[current_interface].sub_api, itransfer);}
+
+static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer) {
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+       int current_interface;
+
+       current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       return priv->usb_interface[current_interface].apib->
+               submit_iso_transfer(priv->usb_interface[current_interface].sub_api, itransfer);}
+
+static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
+{
+       struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
+       struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       int current_interface;
+
+       current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
+       if (current_interface < 0) {
+               usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
+               return LIBUSB_ERROR_NOT_FOUND;
+       }
+
+       return priv->usb_interface[current_interface].apib->
+               clear_halt(priv->usb_interface[current_interface].sub_api, dev_handle, endpoint);}
+
+static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+
+       return priv->usb_interface[transfer_priv->interface_number].apib->
+               abort_control(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);}
+
+static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+
+       return priv->usb_interface[transfer_priv->interface_number].apib->
+               abort_transfers(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);}
+
+static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
+{
+       struct windows_device_priv *priv = _device_priv(dev_handle->dev);
+       int r;
+       uint8_t i; 
+       bool available[SUB_API_MAX];
+       for (i = 0; i<SUB_API_MAX; i++) {
+               available[i] = false;
+       }
+       for (i=0; i<USB_MAXINTERFACES; i++) {
+               if ( (priv->usb_interface[i].apib->id == USB_API_WINUSBX)
+                 && (priv->usb_interface[i].sub_api != SUB_API_NOTSET) ) {
+                       available[priv->usb_interface[i].sub_api] = true;
+               }
+       }
+       for (i=0; i<SUB_API_MAX; i++) {
+               if (available[i]) {
+                       r = usb_api_backend[USB_API_WINUSBX].reset_device(i, dev_handle);
+                       if (r != LIBUSB_SUCCESS) {
+                               return r;
+                       }
+               }
+       }
+       return LIBUSB_SUCCESS;
+}
+
+static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
+{
+       struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
+       struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
+       struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
+
+       return priv->usb_interface[transfer_priv->interface_number].apib->
+               copy_transfer_data(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer, io_size);
+}