VDDQueryDMA

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