PVIDEO_HW_TIMER callback function (video.h)

HwVidTimer is a video miniport driver routine called at timed intervals by the video port driver.

Syntax

PVIDEO_HW_TIMER PvideoHwTimer;

void PvideoHwTimer(
  PVOID HwDeviceExtension
)
{...}

Parameters

HwDeviceExtension

Pointer to the miniport driver's per-adapter storage area. For more information, see Device Extensions.

Return value

None

Remarks

HwVidTimer is an optional miniport driver function to which calls are enabled with VideoPortStartTimer and disabled with VideoPortStopTimer.

Any miniport driver can have a HwVidTimer function. For example, a HwVidTimer function could be used to read the state of the "VGA" registers on a high-end video adapter so that the miniport driver can emulate VGA-compatible behavior.

After a call to VideoPortStartTimer, the video port driver calls a miniport driver's HwVidTimer function at approximately one-second intervals until the miniport driver calls VideoPortStopTimer.

Note that the HwVidTimer function must not disable the timer with a call to VideoPortStopTimer.

HwVidTimer must not be made pageable.

Requirements

See also

VideoPortStartTimer

VideoPortStopTimer