DXGKDDI_PATCH callback function (d3dkmddi.h)

Article
05/26/2023

The DxgkDdiPatch function assigns physical addresses to the given direct memory access (DMA) buffer before the DMA buffer is submitted to the graphics hardware.

Syntax

DXGKDDI_PATCH DxgkddiPatch;

NTSTATUS DxgkddiPatch(
  [in] IN_CONST_HANDLE hAdapter,
  [in] IN_CONST_PDXGKARG_PATCH pPatch
)
{...}

Parameters

[in] hAdapter

A handle to a context block that is associated with a display adapter. The display miniport driver previously provided this handle to the Microsoft DirectX graphics kernel subsystem in the MiniportDeviceContext output parameter of the DxgkDdiAddDevice function.

[in] pPatch

A pointer to a DXGKARG_PATCH structure that describes the DMA buffer to be patched with physical addresses.

Return value

Returns STATUS_SUCCESS upon successful completion. If the driver instead returns an error code, the operating system causes a system bugcheck to occur. For more information, see the following Remarks section.

Remarks

The DxgkDdiPatch function must assign physical addresses to the DMA buffer in place. Therefore, when the display miniport driver generates the DMA buffer, the driver must ensure that space is available in the DMA buffer to insert instructions that are required to handle physical addresses. Note that physical addresses might correspond to video memory, AGP/PCI Express memory, or system memory.

The driver must examine the supplied patch-location list in the pPatchLocationList member of the DXGKARG_PATCH structure that is pointed to by the pPatch parameter to identify places in the DMA buffer that must be patched with physical addresses. The supplied allocation list (which is specified by the pAllocationList member of DXGKARG_PATCH) also contains the physical addresses that the video memory manager generates. The call to the driver's DxgkDdiPatch function is the last chance for the driver to modify the content of the DMA buffer before the DMA buffer is submitted to the graphics processing unit (GPU). Note that the driver can patch a DMA buffer multiple times in scenarios where the DMA buffer is preempted.

The driver can patch the value that is supplied in the SubmissionFenceId member of DXGKARG_PATCH into the fence command at the end of the DMA buffer. For more information about this member, see Supplying Fence Identifiers.

If the driver returns an error code, the Microsoft DirectX graphics kernel subsystem causes a system bugcheck to occur. In a crash dump file, the error is noted by the message BugCheck 0x119, which has the following four parameters.

0x3
A pointer to an internal scheduler data structure
A pointer to an internal scheduler data structure
A pointer to an internal scheduler data structure

DxgkDdiPatch should be made pageable.

Requirements

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