확장 최소화

WdfDmaEnablerGetMaximumScatterGatherElements method

[Applies to KMDF only]

The WdfDmaEnablerGetMaximumScatterGatherElements method returns the maximum number of scatter/gather elements that the device and driver support, for a specified DMA enabler object.

Syntax


size_t WdfDmaEnablerGetMaximumScatterGatherElements(
  [in]  WDFDMAENABLER DmaEnabler
);

Parameters

DmaEnabler [in]

A handle to a DMA enabler object that the driver obtained from a previous call to WdfDmaEnablerCreate.

Return value

If the driver previously called WdfDmaEnablerSetMaximumScatterGatherElements, WdfDmaEnablerGetMaximumScatterGatherElements returns the value that the driver specified in the previous call. Otherwise, WdfDmaEnablerGetMaximumScatterGatherElements returns WDF_DMA_ENABLER_UNLIMITED_FRAGMENTS, which indicates that there is no limit to the number of scatter/gather elements.

A bug check occurs if the driver supplies an invalid object handle.

Remarks

For more information about this method, see Enabling DMA Transactions.

Examples

The following code example obtains the maximum number of scatter/gather elements for a specified DMA enabler object.


size_t maxElements;

maxElements = WdfDmaEnablerGetMaximumScatterGatherElements(DmaEnabler);
 

Requirements

Minimum KMDF version

1.0

Header

Wdfdmaenabler.h (include Wdf.h)

Library

Wdf01000.sys (see Framework Library Versioning.)

IRQL

<=DISPATCH_LEVEL

DDI compliance rules

DriverCreate, KmdfIrql, KmdfIrql2

See also

WdfDmaEnablerCreate
WdfDmaEnablerSetMaximumScatterGatherElements

 

 

Send comments about this topic to Microsoft

표시:
© 2014 Microsoft