[alsa-devel] Power management state flow in ALSA

[Takashi Iwai]

At Wed, 30 May 2007 11:52:31 +0530,
Nobin Mathew wrote:
> 
> I am having a doubt regarding ALSA power management.
> 
> My understanding of APM suspend() is like this.
> 
> Freeze the ALSA apps
> 
> Call ALSA driver suspend ()
> 
> in the ALSA suspend() function it saves the current state of substream
> and changes the state of substream to SUSPENDED.
> 
> My understanding of APM resume() is like this
> 
> Call ALSA driver resume ()
> 
> Activate the ALSA apps
> 
> In ALSA resume function it restores the saved state of substream.
> 
> 
> So my question is when ALSA app will get to know the SUSPENDED state
> of substream.???

When issuing any syscalls.  Then you'll get ESTRPIPE error, which
indicitaes the stream is in the SUSPEND state.


Takashi