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The VideoPortMapDmaMemory function is obsolete in Windows 2000 and later.
VideoPortMapDmaMemory maps a range of memory for use in DMA transfers.
Syntax
VIDEOPORT_DEPRECATED VIDEOPORT_API PDMA VideoPortMapDmaMemory(
[in] IN PVOID HwDeviceExtension,
[in] IN PVIDEO_REQUEST_PACKET pVrp,
[in] IN PHYSICAL_ADDRESS BoardAddress,
[in] IN PULONG Length,
[in] IN PULONG InIoSpace,
[in] IN PVOID MappedUserEvent,
[in] IN PVOID DisplayDriverEvent,
[in, out] IN OUT PVOID *VirtualAddress
);
Parameters
[in] HwDeviceExtension
Pointer to the miniport driver's device extension.
[in] pVrp
Pointer to a VIDEO_REQUEST_PACKET.
[in] BoardAddress
Specifies the adapter's beginning address.
[in] Length
Specifies the length, in bytes, of the range of memory.
[in] InIoSpace
Indicates the location of the range. This parameter can be one of the following values:
Value | Meaning |
---|---|
VIDEO_MEMORY_SPACE_DENSE | Memory is densely mapped and linear. |
VIDEO_MEMORY_SPACE_IO | The range is in system I/O space. Should not be set by the display driver. |
VIDEO_MEMORY_SPACE_MEMORY | The range is in memory space. Should not be set by the display driver. |
VIDEO_MEMORY_SPACE_P6CACHE | P6 MTRR caching, which is equivalent to write-combine caching. (kernel and user mode). |
VIDEO_MEMORY_SPACE_USER_MODE | Memory pointer for application use. |
[in] MappedUserEvent
Is reserved for system use.
[in] DisplayDriverEvent
Is reserved for system use.
[in, out] VirtualAddress
Is reserved for system use.
Return value
VideoPortMapDmaMemory always returns NULL.
Remarks
See Bus-Master DMA in Video Miniport Drivers for information about packet-based and common-buffer DMA transfers.
Requirements
Requirement | Value |
---|---|
Minimum supported client | Available in Windows 2000 and later versions of the Windows operating systems. |
Target Platform | Desktop |
Header | video.h (include Video.h) |
Library | Videoprt.lib |
DLL | Videoprt.sys |