VideoPortCompleteDma function

The VideoPortCompleteDma function flushes any data remaining in a bus-master adapter's internal cache at the end of a DMA transfer operation, and then frees the previously allocated map registers and scatter/gather list used in scatter/gather DMA operations.

Syntax


VP_STATUS VideoPortCompleteDma(
  _In_ PVOID                   HwDeviceExtension,
  _In_ PVP_DMA_ADAPTER         VpDmaAdapter,
  _In_ PVP_SCATTER_GATHER_LIST VpScatterGather,
  _In_ BOOLEAN                 WriteToDevice
);

Parameters

HwDeviceExtension [in]

Pointer to the miniport driver's device extension.

VpDmaAdapter [in]

Pointer to a VP_DMA_ADAPTER structure that represents the bus-master adapter. This structure was returned by a call to VideoPortGetDmaAdapter.

VpScatterGather [in]

Pointer to the VP_SCATTER_GATHER_LIST structure previously passed to the miniport driver callback routine, HwVidExecuteDma.

WriteToDevice [in]

Specifies the direction of the DMA transfer. A value of TRUE denotes a transfer from the buffer to the device, and a value of FALSE denotes a transfer from the device to the buffer.

Return value

VideoPortCompleteDma returns NO_ERROR.

Remarks

The video miniport driver should call VideoPortCompleteDma immediately to free up system resources after a DMA transfer has been completed.

It is important to note that the scatter/gather list built by VideoPortStartDma becomes invalid when VideoPortCompleteDma is called..

Requirements

Target platform

Version

Available in Windows XP and later versions of the Windows operating systems.

Header

Video.h (include Video.h)

Library

Videoprt.lib

DLL

Videoprt.sys

IRQL

<=DISPATCH_LEVEL

See also

VideoPortGetDmaAdapter
VideoPortStartDma
VP_DMA_ADAPTER
VP_SCATTER_GATHER_LIST

 

 

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