PCAM_FREE_BW_ROUTINE callback function (usbcamdi.h)
[CamFreeBandwidth is not supported and may be altered or unavailable in the future. Instead, use CamFreeBandwidthEx. ]
A camera minidriver's CamFreeBandwidth callback function selects an alternate setting within the USB video streaming interface that uses no bandwidth.
Syntax
PCAM_FREE_BW_ROUTINE PcamFreeBwRoutine;
NTSTATUS PcamFreeBwRoutine(
PDEVICE_OBJECT BusDeviceObject,
PVOID DeviceContext
)
{...}
Parameters
BusDeviceObject
Pointer to the camera minidriver's device object created by the USB hub.
DeviceContext
Pointer to the camera minidriver's device context.
Return value
CamFreeBandwidth returns STATUS_SUCCESS or an appropriate error code.
Remarks
Camera minidrivers that must maintain backward compatibility with the original USBCAMD must use the USBCAMD_DEVICE_DATA structure and its associated callback functions (that is, callback functions that do not contain the "Ex" suffix).
USBCAMD calls the camera minidriver's CamFreeBandwidth callback function after the isochronous video stream has stopped.
Typically, this function calls the USBCAMD_SelectAlternateInterface service to select the correct alternate interface and prepare for streaming video.
This function is required.
Requirements
| Requirement | Value |
|---|---|
| Target Platform | Desktop |
| Header | usbcamdi.h (include Usbcamdi.h) |