The WdfUsbTargetDeviceCyclePortSynchronously method power-cycles the USB port to which a specified device is attached.
NTSTATUS WdfUsbTargetDeviceCyclePortSynchronously( [in] WDFUSBDEVICE UsbDevice );
- UsbDevice [in]
A handle to a USB device object that was obtained from a previous call to WdfUsbTargetDeviceCreate.
WdfUsbTargetDeviceCyclePortSynchronously returns the I/O target's completion status value if the operation succeeds. Otherwise, this method might return one of the following values:
The caller's IRQL was invalid.
This method also might return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
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.
The following code example power-cycles a specified device's USB port.
NTSTATUS status; status = WdfUsbTargetDeviceCyclePortSynchronously(UsbDevice);
|Available in version 1.0 and later versions of KMDF.|
|Wdf<MajorVersionNumber>000.sys (see Framework Library Versions.)|