DXGKDDI_VIDPNTOPOLOGY_GETNUMPATHSFROMSOURCE callback function (d3dkmddi.h)

• 05/10/2018
• 2 minutes to read

The pfnGetNumPathsFromSource function returns the number of video present paths that contain a specified video present source.

Syntax

DXGKDDI_VIDPNTOPOLOGY_GETNUMPATHSFROMSOURCE DxgkddiVidpntopologyGetnumpathsfromsource;

NTSTATUS DxgkddiVidpntopologyGetnumpathsfromsource(
  IN_CONST_D3DKMDT_HVIDPNTOPOLOGY hVidPnTopology,
  IN_CONST_D3DDDI_VIDEO_PRESENT_SOURCE_ID VidPnSourceId,
  OUT_PSIZE_T pNumPathsFromSource
)
{...}

Parameters

hVidPnTopology

[in] 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.

VidPnSourceId

[in] An integer that identifies a particular video present source.

pNumPathsFromSource

[out] A pointer to a SIZE_T-typed variable that receives the number of paths that contain the specified source.

Return value

The pfnGetNumPathsFromSource function returns one of the following values:

Remarks

A topology is a collection paths, each of which contains a (source, target) pair. It is possible for a particular source to appear in more than one path. For example, one source can be paired with two distinct targets in the case of a clone view.

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.

The D3DKMDT_HVIDPNTOPOLOGY data type is defined in D3dkmdt.h.

The D3DDDI_VIDEO_PRESENT_SOURCE_ID data type is defined in D3dukmdt.h.

Requirements

See also

pfnGetNumPaths