ALSA sound suspend/resume

Joerg Reisenweber joerg at openmoko.org
Wed Jun 11 11:08:16 CEST 2008


Am Mi  11. Juni 2008 schrieb Andy Green:
> Somebody in the thread at some point said:
> 
> |> to do the same, when setup and sequenced properly (on 8753 there are).
> |> I'll come back with more, when I read about it in the amp's specs
> |> eventually. Which audio output is it we talk about (hp, earphone, spk?
> |> BT even? GTA01/02?)
> 
> | It is the speaker output I have set when I suspend/resume so I suspected
> | the speaker amp.
> |
> | Thanks for the info. Any help is greatly appreciated.
> 
> WM8753 datasheet (p89) explicitly goes through the steps to power stuff
> down without pops (was reading this yesterday), but it didn't bank on an
> external amp in the way.  You're meant to disable the output pins and
> then kill Vref, then pull power.  I guess we should do that and then
> disable the external amp.  I'll have a go at it.

I think we should shut down 4853 first, and start last. It will do whatever 
it's doing on power-up/down anyway. *IF* we would create plops on 8753, no 
need to have 4853 up and amplify them.
Anyway I didn't look to the 4853 ds actually. But OTOH what could be in here?

And if we would start 4853 first, or power down last, my anti-plop scheme from 
above is moot.


/jOERG
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