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VideoPortLockPages function

The VideoPortLockPages function is obsolete in Windows 2000 and later. Use VideoPortLockBuffer in place of this function.

VideoPortLockPages locks the specified virtual memory and possibly performs part or all of a DMA transfer.

Syntax


BOOLEAN VideoPortLockPages(
  _In_     PVOID HwDeviceExtension,
  _Inout_  PVIDEO_REQUEST_PACKET pVrp,
  _In_     PEVENT pUEvent,
  _In_     PEVENT pDisplayEvent,
  _In_     DMA_FLAGS DmaFlags
);

Parameters

HwDeviceExtension [in]

Pointer to the miniport driver's device extension.

pVrp [in, out]

Pointer to a VIDEO_REQUEST_PACKET structure. The miniport driver must have set InputBuffer and InputBufferLength to contain the virtual address and the size in bytes, respectively, of the memory to be locked for the transfer. This memory was allocated by the display driver and passed to the miniport driver through an IOCTL. The video port returns a pointer to and the size in bytes of the scatter/gather list in OutputBuffer and OutputBufferLength, respectively.

pUEvent [in]

Pointer to a mapped user event that is to be set by the miniport driver, or NULL. The user event was mapped by the display driver and passed to the miniport driver through an IOCTL.

pDisplayEvent [in]

Pointer to an event that is to be set by the miniport driver, or NULL. This event was created by and received from the display driver through an IOCTL.

DmaFlags [in]

Specifies the action to be performed. This parameter must be one of the following values:

ValueMeaning

VideoPortDmaInitOnly

VideoPortLockPages locks the requested memory.

VideoPortKeepPagesLocked

VideoPortLockPages takes no action.

VideoPortUnlockAfterDma

VideoPortLockPages takes no action.

 

Return value

VideoPortLockPages returns TRUE upon successful completion of the action requested of it. It returns FALSE if the DmaFlags parameter is not equal to VideoPortDmaInitOnly.

Remarks

See Bus-Master DMA in Video Miniport Drivers for information about packet-based and common-buffer DMA transfers.

VideoPortLockPages cannot be called from an ISR or DPC.

Requirements

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

See also

VideoPortLockBuffer

 

 

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