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The IOCTL_INTERNAL_USB_REGISTER_COMPOSITE_DEVICE I/O request registers the driver of a USB multi-function device (composite driver) with the underlying USB driver stack.

This request is sent by a driver that replaces the Microsoft-provided composite driver, Usbccgp.sys, and implements the function suspend and remote wake-up feature, per the Universal Serial Bus (USB) 3.0 specification.

IOCTL_INTERNAL_USB_REGISTER_COMPOSITE_DEVICE is a kernel-mode I/O control request. This request targets the USB hub physical device object (PDO). This request must be sent at an interrupt request level (IRQL) of PASSIVE_LEVEL.

Input Parameters

Parameters.Others.Argument1 is a pointer to a caller-allocated and initialized REGISTER_COMPOSITE_DEVICE structure that contains information about the parent driver. To initialize the structure, call the USBD_BuildRegisterCompositeDevice routine.

The AssociatedIrp.SystemBuffer member points to a caller-allocated buffer that is large enough to hold an array of function handles (typed USBD_FUNCTION_HANDLE) for functions in the USB composite device. The number of elements in the array is indicated by the FunctionCount member of REGISTER_COMPOSITE_DEVICE. To obtain the number of functions, inspect the descriptors returned by a get-configuration request.

Output Parameters

On output, the buffer pointed to by AssociatedIrp.SystemBuffer member is filled with function handles for functions in the multi-function device.

I/O Status Block

The USB driver stack sets Irp->IoStatus.Status to STATUS_SUCCESS if the request completes successfully. STATUS_SUCCESS indicates that the function handles are valid.

In case of an error, Irp->IoStatus.Status contains an appropriate error status. For example, if the composite driver sends the request more than once, the Status is set to STATUS_INVALID_DEVICE_REQUEST.


The purpose of IOCTL_INTERNAL_USB_REGISTER_COMPOSITE_DEVICE is for the composite driver to send a registration request to the USB driver stack. In the registration request, the composite driver specifies the number of functions supported by the device. Therefore, you must send the IOCTL_INTERNAL_USB_REGISTER_COMPOSITE_DEVICE request after determining the number of functions. Typically, that information is retrieved in the composite driver's start-device routine (IRP_MN_START_DEVICE). Note that number of interfaces in a configuration can indicate the number of functions, but not always. Certain multi-function devices expose multiple interfaces related to one function. To obtain the number of functions, you must inspect various descriptors that are related to a particular configuration. Those descriptors can be obtained through a get-descriptor request.

In response to the registration request, the USB driver stack provides a list of handles for the functions in the device. For a code example, see How to Register a Composite Device.

After the composite driver is registered, the driver can configure the remote wake-up feature. By using the function handle, the composite driver can send a request (see IOCTL_INTERNAL_USB_REQUEST_REMOTE_WAKE_NOTIFICATION) to get remote wake-up notifications from the USB driver stack, when the associated function sends a resume signal.

In order to remove the composite driver's association with the USB driver stack and release all resources that are allocated for registration, the driver must send the IOCTL_INTERNAL_USB_UNREGISTER_COMPOSITE_DEVICE request.



Windows 8


Usbioctl.h (include Usbioctl.h)



See also

How to Register a Composite Device



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