WdfUsbTargetDeviceCyclePortSynchronously function (wdfusb.h)

[Applies to KMDF only]

The WdfUsbTargetDeviceCyclePortSynchronously method power-cycles the USB port to which a specified device is attached.

Syntax

NTSTATUS WdfUsbTargetDeviceCyclePortSynchronously(
  [in] WDFUSBDEVICE UsbDevice
);

Parameters

[in] UsbDevice

A handle to a USB device object that was obtained from a previous call to WdfUsbTargetDeviceCreateWithParameters.

Return value

WdfUsbTargetDeviceCyclePortSynchronously returns the I/O target's completion status value if the operation succeeds. Otherwise, this method might return one of the following values:

This method also might return other NTSTATUS values.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

Power-cycling a port causes the device to be surprise-removed and re-enumerated. A driver might request a power cycle after it has loaded firmware into a device.

Before the framework cycles the I/O target's USB port, it cancels all I/O requests that remain in the I/O target's queue. The driver must not send additional I/O requests to the I/O target until WdfUsbTargetDeviceCyclePortSynchronously returns.

The driver must call WdfIoTargetStop before it calls WdfUsbTargetDeviceCyclePortSynchronously.

For more information about the WdfUsbTargetDeviceCyclePortSynchronously method and USB I/O targets, see USB I/O Targets.

Examples

The following code example power-cycles a specified device's USB port.

NTSTATUS status;

status = WdfUsbTargetDeviceCyclePortSynchronously(UsbDevice);

Requirements

See also

WdfUsbTargetDeviceCreateWithParameters