DXGKDDI_VIDPNTOPOLOGY_ACQUIREPATHINFO callback function (d3dkmddi.h)

Article
02/22/2024

The pfnAcquirePathInfo function returns a descriptor of the video present path specified by a video present source and a video present target within a particular VidPN topology.

Syntax

DXGKDDI_VIDPNTOPOLOGY_ACQUIREPATHINFO DxgkddiVidpntopologyAcquirepathinfo;

NTSTATUS DxgkddiVidpntopologyAcquirepathinfo(
  [in]  IN_CONST_D3DKMDT_HVIDPNTOPOLOGY hVidPnTopology,
  [in]  IN_CONST_D3DDDI_VIDEO_PRESENT_SOURCE_ID VidPnSourceId,
  [in]  IN_CONST_D3DDDI_VIDEO_PRESENT_TARGET_ID VidPnTargetId,
  [out] DEREF_OUT_CONST_PPD3DKMDT_VIDPN_PRESENT_PATH ppVidPnPresentPathInfo
)
{...}

Parameters

[in] hVidPnTopology

A handle to a VidPN topology object. The display miniport driver previously obtained this handle by calling the pfnGetTopology function of the DXGK_VIDPN_INTERFACE interface.

[in] VidPnSourceId

An integer that identifies a video present source.

[in] VidPnTargetId

An integer that identifies a video present target.

[out] ppVidPnPresentPathInfo

A pointer to a variable that receives a pointer to a D3DKMDT_VIDPN_PRESENT_PATH structure that describes the requested path.

Return value

The pfnAcquirePathInfo function returns one of the following values:

Return code	Description
STATUS_SUCCESS	The function succeeded.
STATUS_GRAPHICS_INVALID_VIDPN_TOPOLOGY	The handle supplied in hVidPnTopology was invalid.

Remarks

When you have finished using the D3DKMDT_VIDPN_PRESENT_PATH structure, you must release the structure by calling pfnReleasePathInfo.

A path contains a (source, target) pair, and a topology is a collection of paths. This function returns a descriptor for the path, in a specified topology, that contains a specified (source, target) pair.

You can enumerate all the paths that belong to a VidPN topology object by calling pfnAcquireFirstPathInfo and then making a sequence of calls to pfnAcquireNextPathInfo.

VidPN source identifiers are assigned by the operating system. DxgkDdiStartDevice, implemented by the display miniport driver, returns the number N of video present sources supported by the display adapter. Then the operating system assigns identifiers 0, 1, 2, ... N - 1.

VidPN target identifiers are assigned by the display miniport driver. DxgkDdiQueryChildRelations, implemented by the display miniport driver, returns an array of DXGK_CHILD_DESCRIPTOR structures, each of which contains an identifier.

The D3DKMDT_HVIDPNTOPOLOGY data type is defined in D3dkmdt.h.

The D3DDDI_VIDEO_PRESENT_SOURCE_ID and D3DDDI_VIDEO_PRESENT_TARGET_ID data types are defined in D3dukmdt.h.

Requirements

Requirement	Value
Minimum supported client	Windows Vista
Target Platform	Desktop
Header	d3dkmddi.h (include D3dkmddi.h)
IRQL	PASSIVE_LEVEL