// dispmprt.h

DXGKDDI_DISPLAYMUX_PRE_SWITCH_AWAY DxgkddiDisplaymuxPreSwitchAway;

NTSTATUS DxgkddiDisplaymuxPreSwitchAway(
  PVOID DriverContext,
  ULONG VidPnTargetId,
  PULONG pSwitchPrivateDataSize
)
{...}
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Windows Driver Kit DDI reference (nc-dispmprt-dxgkddi_displaymux_pre_switch_away)

Description

Dxgkrnl calls the kernel-mode display driver's (KMD) DxgkddiDisplayMuxPreSwitchAway function to notify the driver that the display currently connected to it is about to be switched away to another GPU.

Parameters

`DriverContext`

[in] Handle to a context block that is associated with a display adapter. KMD's DxgkDdiAddDevice function previously provided this handle to Dxgkrnl.

`VidPnTargetId`

[in] The VidPN target that the DDI is being called for.

`pSwitchPrivateDataSize`

[out] Pointer to a ULONG variable in which the driver writes the size in bytes of the switch private data that will be passed to the other GPU during the switch.

Return value

DxgkddiDisplayMuxPreSwitchAway returns STATUS_SUCCESS if it succeeds. Otherwise, it returns an appropriate NT_STATUS error code.

Remarks

This DDI is called under synchronization level 2.

For more information, see Automatic Display Switch.

DXGKDDI_DISPLAYMUX_PRE_SWITCH_AWAY - NtDoc