WdfDmaEnablerSetMaximumScatterGatherElements function (wdfdmaenabler.h)

Article
02/22/2024

[Applies to KMDF only]

The WdfDmaEnablerSetMaximumScatterGatherElements method sets the maximum number of scatter/gather elements that a device supports, for a specified DMA enabler object.

Syntax

void WdfDmaEnablerSetMaximumScatterGatherElements(
  [in] WDFDMAENABLER DmaEnabler,
  [in] size_t        MaximumFragments
);

Parameters

[in] DmaEnabler

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

[in] MaximumFragments

The maximum number of scatter/gather elements that the driver and device can support.

Return value

None

Remarks

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

If your driver calls WdfDmaEnablerSetMaximumScatterGatherElements, it must do so within the EvtDriverDeviceAdd or EvtDevicePrepareHardware callback function.

If your driver does not call WdfDmaEnablerSetMaximumScatterGatherElements, the framework uses a default value of WDF_DMA_ENABLER_UNLIMITED_FRAGMENTS, which means that there is no limit to the number of scatter/gather elements.

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

Examples

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

WdfDmaEnablerSetMaximumScatterGatherElements(
                                             DmaEnabler, 
                                             NIC_MAX_PHYS_BUF_COUNT
                                             );

Requirements

Requirement	Value
Target Platform	Universal
Minimum KMDF version	1.0
Header	wdfdmaenabler.h (include Wdf.h)
Library	Wdf01000.sys (see Framework Library Versioning.)
IRQL	PASSIVE_LEVEL
DDI compliance rules	DriverCreate(kmdf), KmdfIrql(kmdf), KmdfIrql2(kmdf), KmdfIrqlExplicit(kmdf)

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