DMA_ADAPTER_INFO_V1 structure (wdm.h)

The DMA_ADAPTER_INFO_V1 structure describes the capabilities of the system DMA controller that is represented by an adapter object.

Syntax

typedef struct _DMA_ADAPTER_INFO_V1 {
  ULONG ReadDmaCounterAvailable;
  ULONG ScatterGatherLimit;
  ULONG DmaAddressWidth;
  ULONG Flags;
  ULONG MinimumTransferUnit;
} DMA_ADAPTER_INFO_V1, *PDMA_ADAPTER_INFO_V1;

Members

ReadDmaCounterAvailable

Whether the counter value in each DMA channel can be read. This member is TRUE if the counter can be read, and is FALSE if it cannot be read.

ScatterGatherLimit

The maximum number of elements in a scatter/gather list that the DMA controller can process in a single scatter/gather DMA transfer.

DmaAddressWidth

The memory address width, in bits, of the DMA controller. The width is expressed as the number of bits in a DMA address. If the DMA address width is less than the memory address width, the platform hardware drives the remaining, high-order memory address bits to zero during a DMA transfer.

Flags

A set of flags that describe the capabilities of the DMA adapter. No flags are currently defined for this member.

MinimumTransferUnit

The size, in bytes, of the minimum transfer unit. The number of bytes specified by an element in a scatter/gather list must be an integer multiple of the minimum transfer unit.

Remarks

The V1 member of the DMA_ADAPTER_INFO structure is a structure of type DMA_ADAPTER_INFO_V1.

A driver calls GetDmaAdapterInfo to obtain information about the hardware capabilities of a system DMA channel. GetDmaAdapterInfo writes this information into the V1 member of a caller-supplied DMA_ADAPTER_INFO structure.

Requirements

See also

DMA_ADAPTER_INFO

GetDmaAdapterInfo