Bewerken

Delen via

VideoPortLockPages function (video.h)

  • Artikel

The VideoPortLockPages function is obsolete in Windows 2000 and later.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

VIDEOPORT_DEPRECATED VIDEOPORT_API BOOLEAN VideoPortLockPages(
  [in]      IN PVOID                     HwDeviceExtension,
  [in, out] IN OUT PVIDEO_REQUEST_PACKET pVrp,
  [in]      IN PEVENT                    pUEvent,
  [in]      IN PEVENT                    pDisplayEvent,
  [in]      IN DMA_FLAGS                 DmaFlags
);

Parameters

[in] HwDeviceExtension

Pointer to the miniport driver's device extension.

[in, out] pVrp

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.

[in] pUEvent

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.

[in] pDisplayEvent

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.

[in] DmaFlags

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

Value Meaning
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

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

See also

VideoPortLockBuffer