DXGK_ALLOCATIONLIST structure

05/10/2018
2 minutes to read

The DXGK_ALLOCATIONLIST structure describes an allocation specification that is used in direct memory access (DMA) buffering.

Syntax

typedef struct _DXGK_ALLOCATIONLIST {
  HANDLE           hDeviceSpecificAllocation;
  struct {
    UINT WriteOperation : 1;
    UINT SegmentId : 5;
    UINT Reserved : 26;
  };
  union {
    PHYSICAL_ADDRESS       PhysicalAddress;
    D3DGPU_VIRTUAL_ADDRESS VirtualAddress;
  };
  PHYSICAL_ADDRESS PhysicalAddress;
} DXGK_ALLOCATIONLIST;

Members

hDeviceSpecificAllocation

[in/out] An open handle to the allocation that is being referenced (that is, the handle that the driver returned in the hDeviceSpecificAllocation member of the DXGK_OPENALLOCATIONINFO structure for the allocation in a call to the driver's DxgkDdiOpenAllocation function).

The following members are embedded in the structure:

WriteOperation

[in/out] A member in the structure that DXGK_ALLOCATIONLIST contains that can hold information about whether the allocation can be written to. Setting this member to 1 indicates that the allocation can be written to anywhere in the DMA buffer.

Setting this member is equivalent to setting the first bit of a 32-bit value (0x00000001).

SegmentId

[in/out] A member in the structure that DXGK_ALLOCATIONLIST contains that can hold information about the identifier of a segment that the allocation was last paged in at. Setting this member to 0 indicates that no pre-patching information is available.

Setting this member is equivalent to setting the second through sixth bit of a 32-bit value (0x0000002E).

Reserved

[in] A member in the structure that DXGK_ALLOCATIONLIST contains that is reserved. This member should be set to 0.

Setting this member is equivalent to setting the remaining 26 bits (0xFFFFFFC0) of a 32-bit value to zeros.

The following members are embedded in a union:

PhysicalAddress

[in/out] A PHYSICAL_ADDRESS data type (which is defined as LARGE_INTEGER) that indicates the physical address, within the segment that SegmentId specifies, where the allocation was last paged-in at. This member is set to zero if no pre-patching information is available.

Supported starting with Windows 10.

VirtualAddress

[in/out] A D3DGPU_VIRTUAL_ADDRESS data type that indicates the virtual address.

Supported starting with Windows 10.

WriteOperation

SegmentId

Reserved

PhysicalAddress

VirtualAddress

Remarks

In the display miniport driver's DxgkDdiRender function, the driver generates a list of DXGK_ALLOCATIONLIST structures for allocation specifications that will be used in a direct memory access (DMA) buffer. The video memory manager uses the list to split and patch DMA buffers appropriately.

Requirements


Minimum supported client	Available in Windows Vista and later versions of the Windows operating systems.
Header	d3dkmddi.h (include D3dkmddi.h)