BOOLEAN HwVidStartIO(
| PVOID HwDeviceExtension, | |
| PVIDEO_REQUEST_PACKET RequestPacket | |
| ); |
Every video miniport driver must have a HwVidStartIO function. The video port driver calls HwVidStartIO in response to each GDI EngDeviceIoControl request, which originates in the corresponding display driver. When HwVidStartIO is called, the miniport driver owns the input video request packet until it completes the requested operation.
Parameters
HwDeviceExtension
Points to the miniport's per-adapter storage area.
RequestPacket
Points to a VRP, which contains all the parameters originally passed to EngDeviceIoControl.
Return Value
HwVidStartIO must return TRUE, indicating that it has completed the request.
Comments
HwVidStartIO must examine the VRP, carry out whatever operation is requested, set the appropriate status in the status block of the VRP, and then return TRUE.
The system video port driver serializes all requests. A miniport driver need not perform any serialization of its own unless it has a HwVidInterrupt function.
However, every miniport's HwVidStartIO function must complete each requested operation or set an appropriate error in the VRP's StatusBlock before it returns control.
See Also
IOCTL_VIDEO_XXX, VIDEO_REQUEST_PACKET, VideoPortSynchronizeExecution