On Wed, Apr 30, 2008 at 12:57 PM, Mark Brown < broonie@opensource.wolfsonmicro.com> wrote:
If what you're trying to do is avoid powering on amplifiers when they are muted then this is best avoided since it often creates problems with pops and clicks due to things getting powered on and off out of the sequence generated by DAPM. If the amplifier is powered on before its inputs then it will amplify any noise generaetd by the inputs when they change power state. This is why ASoC mute controls for amplifiers are normally independent of their power controls.
I was looking do we have possible driver bug here and answer is no. Driver keeps output state powered during playback if associated endpoint is enabled with snd_soc_dapm_set_endpoint and unpowered otherwise.
So as with Mark's comment, the patch is unnecessary.
Jarkko