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nf-portcls-iportwavecyclic-notify.md

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UID title description old-location tech.root ms.date keywords ms.keywords req.header req.include-header req.target-type req.target-min-winverclnt req.target-min-winversvr req.kmdf-ver req.umdf-ver req.ddi-compliance req.unicode-ansi req.idl req.max-support req.namespace req.assembly req.type-library req.lib req.dll req.irql targetos req.typenames f1_keywords topic_type api_type api_location api_name
NF:portcls.IPortWaveCyclic.Notify
IPortWaveCyclic::Notify (portcls.h)
Learn how the Notify method notifies the port driver that an interrupt indicating the progress of the DMA pointer has occurred. It should be called from the miniport driver's interrupt service routine (ISR).
audio\iportwavecyclic_notify.htm
audio
05/08/2018
IPortWaveCyclic::Notify
IPortWaveCyclic interface [Audio Devices],Notify method, IPortWaveCyclic.Notify, IPortWaveCyclic::Notify, Notify, Notify method [Audio Devices], Notify method [Audio Devices],IPortWaveCyclic interface, audio.iportwavecyclic_notify, audmp-routines_8b2252d3-100f-4e4a-b5ca-cdaf0c12834e.xml, portcls/IPortWaveCyclic::Notify
portcls.h
Portcls.h
Universal
Any level
Windows
IPortWaveCyclic::Notify
portcls/IPortWaveCyclic::Notify
APIRef
kbSyntax
COM
portcls.h
IPortWaveCyclic::Notify

IPortWaveCyclic::Notify

-description

The Notify method notifies the port driver that an interrupt indicating the progress of the DMA pointer has occurred. It should be called from the miniport driver's interrupt service routine (ISR).

-parameters

-param ServiceGroup [in]

Pointer to the miniport driver's IServiceGroup object.

-remarks

This method is vital for accurate timing. Miniport drivers typically call this method in response to a notification interrupt after having cleared the interrupt source. Although the miniport driver is free to use other methods for determining when to call this method, precise timing is important and should be maintained.

When an adapter driver installs an ISR, it submits a ServiceContext parameter along with the ISR's entry point (for details, see Providing ISR Context Information). When the interrupt occurs, the operating system calls the ISR and passes ServiceContext as a call parameter to the ISR. Although the meaning of the ServiceContext parameter is known only to the driver developer, it is typically a pointer to the miniport object. The ISR uses this pointer to access information about the miniport object.

The port driver calls the IMiniportWaveCyclicStream::SetNotificationFreq method to specify the frequency with which the ISR should call the Notify method. In all current Windows releases, the port driver specifies a regular interval of 10 milliseconds between successive notifications. This value might change in a future release.

The ServiceGroup parameter follows the reference-counting conventions for COM objects.

-see-also

IMiniportWaveCyclicStream::SetNotificationFreq

IPortWaveCyclic

IServiceGroup