VideoPortAcquireSpinLockAtDpcLevel function

The VideoPortAcquireSpinLockAtDpcLevel function acquires a spin lock when the caller is already running at IRQL = DISPATCH_LEVEL.

Syntax


VOID VideoPortAcquireSpinLockAtDpcLevel(
  _Inout_ PVOID      HwDeviceExtension,
  _In_    PSPIN_LOCK SpinLock
);

Parameters

HwDeviceExtension [in, out]

Pointer to the miniport driver's device extension.

SpinLock [in]

Pointer to a memory location that contains the spin lock.

Return value

None

Remarks

Miniport drivers call VideoPortAcquireSpinLockAtDpcLevel instead of VideoPortAcquireSpinLock for better driver performance if and only if they are already running at IRQL = DISPATCH_LEVEL.

If a miniport driver is running at IRQL < DISPATCH_LEVEL, it should call VideoPortAcquireSpinLock to have IRQL raised by that routine. VideoPortAcquireSpinLockAtDpcLevel requires the caller to be running already at IRQL = DISPATCH_LEVEL, so no raise is necessary.

The caller should release the spin lock with VideoPortReleaseSpinLockFromDpcLevel as quickly as possible.

Requirements

Target platform

Desktop

Version

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

Header

Video.h (include Video.h)

Library

Videoprt.lib

DLL

Videoprt.sys

IRQL

DISPATCH_LEVEL (see Remarks section)

See also

VideoPortAcquireSpinLock
VideoPortReleaseSpinLockFromDpcLevel

 

 

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