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Finding and Opening a HID Collection

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This section describes how user-mode applications and kernel-mode drivers find and open a top-level HID collection.

User-Mode Application

Microsoft Windows provides device installation routines (SetupDiXxx functions) to find and identify the HIDClass devices. Windows provides other Win32 functions to initialize and connect to a HID collection.

After a user-mode application is loaded, it does the following sequence of operations:

  • Calls HidD_GetHidGuid to obtain the system-defined GUID for HIDClass devices.

  • Calls SetupDiGetClassDevs to obtain a handle to an opaque device information set that describes the device interfaces supported by all the HID collections currently installed in the system. The application should specify DIGCF_PRESENT and DIGCF_DEVICEINTERFACE in the Flags parameter that is passed to SetupDiGetClassDevs.

  • Calls SetupDiEnumDeviceInterfaces repeatedly to retrieve all the available interface information.

  • Calls SetupDiGetDeviceInterfaceDetail to format interface information for each collection as a SP_INTERFACE_DEVICE_DETAIL_DATA structure. The DevicePath member of this structure contains the user-mode name that the application uses with the Win32 function CreateFile to obtain a file handle to a HID collection.

  • Calls CreateFile to obtain a file handle to a HID collection.

Kernel-Mode Driver

If a kernel-mode driver is a function or filter driver, it has attached a device object to the HID collection's device stack. The driver has to only use a create request to open the device.

If the driver is not a function or filter driver, it typically uses Plug and Play notification to find a collection. After finding a collection, the driver uses a create request to open the collection.