[alsa-devel] [PATCH] ASoC: core: Allow digital mute for capture

[Vinod Koul]

On Wed, Feb 06, 2013 at 05:59:16PM +0000, Mark Brown wrote:
> Help avoid noise from the power up of the capture path propagating through
> into the start of the recording (especially noise caused by the ramp of
> microphone biases) by keeping the capture muted until after we've finished
> powering things up with DAPM in the same manner we do for playback. This
> allows us to take advantage of soft mute support in the hardware more
> effectively and is more consistent.
> 
> The core code using the existing digital mute operation is updated to take
> advantage of this. Some additional cases in the soc-pcm code and suspend
> will need separate handling but these are less practically relevant than
> the main runtime stream start/stop case.
> 
> Rather than refactor the digital mute function in every single driver a
> new operation is added for drivers taking advantage of this functionality,
> the old operation should be phased out over time.
> 
> Signed-off-by: Mark Brown <broonie at opensource.wolfsonmicro.com>
Acked-by Vinod Koul <vinod.koul at intel.com>