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VideoPortMapDmaMemory function (video.h)

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The VideoPortMapDmaMemory function is obsolete in Windows 2000 and later.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