[alsa-devel] [PATCH 4/4] ASoC: tlv320dac33: Support for turning off the codec in BIAS_STANDBY

Peter Ujfalusi peter.ujfalusi at nokia.com
Fri Apr 30 11:45:38 CEST 2010

On Friday 30 April 2010 11:41:00 ext Mark Brown wrote:
> On Fri, Apr 30, 2010 at 10:31:55AM +0300, Peter Ujfalusi wrote:
> > When the codec is in STANDBY we can actually turn it off.
> > When the codec is off, than the associated regulator can be also turned
> > off (if the number of users on the regulator is 0).
> You can just set idle_bias_off in the CODEC and then the core will push
> you down into _BIAS_OFF.

Good idea. Needed some code movement, but works fine. Thanks.

> > There are few scenarios, which has to be taken care::
> > 1. Analog bypass caused BIAS_STANDBY -> BIAS_ON
> > 
> >    We need to power on the codec, and do the chip init, but we does not
> >    need to execute the playback related configuration
> Moving the playback related configuration into events on the DAC widgets
> (or probably a supply connected to the DAC widgets) seems like a good
> move for a lot of these scenarios?  The core will then take care of
> ensuring that the startup sequence for the playback is called for you
> and the states can do what they're supposed to more directly.

This is not working.
Actually it works, if we come from BIAS_OFF, but...
If I restart the playback fast (within asoc timeout for BIAS change), than the 
widget will not get event (since it is still powered). This means that I can not 
do the needed reconfiguration for the tlv320dac33 -> audio breaks.

I will keep the current logic, but move it a bit with the idle_bias_off change.

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