IPortWaveCyclic::Notify method

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).


void Notify(
  [in] PSERVICEGROUP ServiceGroup


ServiceGroup [in]

Pointer to the miniport driver's IServiceGroup object.

Return value



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.


Target platform



Portcls.h (include Portcls.h)


Any level

See also




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