[wdmaudiodev] PortCls behavior on power state change
- From: Eugene Muzychenko <eugene@xxxxxxxxxxxxxx>
- To: wdmaudiodev@xxxxxxxxxxxxx
- Date: Tue, 10 Mar 2015 11:44:23 +0600
Hello!
In "IPowerNotify" and "Implementing IPowerNotify" topics, MSDN Library
says that port driver PAUSES audio streams before calling
PowerChangeNotify. But really, when going to sleep/hibernate state,
port driver STOPS all miniport streams by calling SetState
(KSSTATE_ACQUIRE) and SetState (KSSTATE_STOP) after calling SetState
(KSSTATE_PAUSE). Doing that, port driver does not revoke mappings from
WavePci miniport.
It is VERY inconvenient to maintain state transitions in such
conditions:
- When going from ACQUIRE to STOP, must release all resources except
needed for mapping list.
- When going from STOP to ACQUIRE, must skip mapping list and amount
variables initialization.
- Each Assert call must check if a "plain" stop transition is
performed or a "simulated" one.
Additionally, MSDN Library says: "PortCls calls the
IPowerNotify::PowerChangeNotify method to individually notify each of
the miniport and stream objects that support the IPowerNotify
interface". But really, port driver never asks stream objects for
IID_IPowerNotify. Only IMiniportWavePci and IMiniportTopology objects
are asked for this interface.
Is there a way to force PortCls to behave as said in documentation? At
least, to just pause stream objects instead of fully stopping them.
Regards,
Eugene
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- » [wdmaudiodev] PortCls behavior on power state change - Eugene Muzychenko
