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NdisMGetDmaAlignment function (ndis.h)

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The NdisMGetDmaAlignment function returns the alignment requirements of the DMA system for a NIC.

Syntax

ULONG NdisMGetDmaAlignment(
  [in] NDIS_HANDLE MiniportAdapterHandle
);

Parameters

[in] MiniportAdapterHandle

An NDIS handle that identifies the miniport adapter for the NIC. This handle was originally passed to the MiniportInitializeEx function.

Return value

Returns a value that specifies the alignment requirements of the DMA system. The miniport driver uses this value to round up the size of a receive buffer to a cache-line size or a multiple of that size when it allocates such a buffer.

Remarks

Note  A miniport driver must have already called NdisMRegisterScatterGatherDma or NdisMRegisterDmaChannel to initialize a scatter/gather DMA channel before calling NdisMGetDmaAlignment.
 
A miniport driver can call the NdisMGetDmaAlignment function to determine alignment requirements for DMA buffers that it allocates. A miniport driver might require increasing the returned value because of additional hardware device restrictions.

Requirements

Requirement Value
Minimum supported client Supported in NDIS 6.0 and later.
Target Platform Universal
Header ndis.h (include Ndis.h)
Library Ndis.lib
IRQL = PASSIVE_LEVEL
DDI compliance rules Irql_Miniport_Driver_Function(ndis)

See also

MiniportInitializeEx

NdisMRegisterScatterGatherDma