BOOL VDDQueryDMA(hVdd, iChannel, pDmaInfo)
IN HANDLE hVdd;
IN WORD iChannel;
IN PVDD_DMA_INFO pDmaInfo;
VDDQueryDMA provides DMA data.
Parameters
hVdd
Identifies the VDD.
iChannel
Specifies the DMA channel to query.
pDmaInfo
Specifies the buffer location where information will be returned.
Return Value
The VDDQueryDMA function returns TRUE if successful. If the function fails then FALSE is returned and an error is logged. The extended error code is ERROR_INVALID_ADDRESS which identifies an invalid channel.
Comments
This function will assist VDDs which are doing performance critical work. Such a VDD does its own DMA transfers and avoids an extra buffer copy, which is the overhead of using VDDRequestDMA
VDDs must call VDDSetDMA to update the state of the virtual DMA controller after completing an operation.
See Also
VDDRequestDMA, VDDSetDMA