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
VideoPortReleaseSpinLockFromDpcLevel