VideoPortAcquireSpinLockAtDpcLevel function (video.h)
The VideoPortAcquireSpinLockAtDpcLevel function acquires a spin lock when the caller is already running at IRQL = DISPATCH_LEVEL.
Syntax
VIDEOPORT_API VOID VideoPortAcquireSpinLockAtDpcLevel(
[in, out] PVOID HwDeviceExtension,
[in] PSPIN_LOCK SpinLock
);
Parameters
[in, out] HwDeviceExtension
Pointer to the miniport driver's device extension.
[in] SpinLock
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
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Windows XP and later versions of the Windows operating systems. |
| Target Platform | Desktop |
| Header | video.h (include Video.h) |
| Library | Videoprt.lib |
| DLL | Videoprt.sys |
| IRQL | DISPATCH_LEVEL (see Remarks section) |