VideoPortMapDmaMemory function

The VideoPortMapDmaMemory function is obsolete in Windows 2000 and later.

VideoPortMapDmaMemory maps a range of memory for use in DMA transfers.

Syntax


PDMA VideoPortMapDmaMemory(
  _In_    PVOID                 HwDeviceExtension,
  _In_    PVIDEO_REQUEST_PACKET pVrp,
  _In_    PHYSICAL_ADDRESS      BoardAddress,
  _In_    PULONG                Length,
  _In_    PULONG                InIoSpace,
  _In_    PVOID                 MappedUserEvent,
  _In_    PVOID                 DisplayDriverEvent,
  _Inout_ PVOID                 *VirtualAddress
);

Parameters

HwDeviceExtension [in]

Pointer to the miniport driver's device extension.

pVrp [in]

Pointer to a VIDEO_REQUEST_PACKET.

BoardAddress [in]

Specifies the adapter's beginning address.

Length [in]

Specifies the length, in bytes, of the range of memory.

InIoSpace [in]

Indicates the location of the range. This parameter can be one of the following values:

ValueMeaning

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.

 

MappedUserEvent [in]

Is reserved for system use.

DisplayDriverEvent [in]

Is reserved for system use.

VirtualAddress [in, out]

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

Target platform

Desktop

Version

Available in Windows 2000 and later versions of the Windows operating systems.

Header

Video.h (include Video.h)

Library

Videoprt.lib

DLL

Videoprt.sys

 

 

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