On Wed, Dec 18, 2013 at 11:27:39AM +0000, Mark Brown wrote:
On Wed, Dec 18, 2013 at 10:53:44AM +0000, Charles Keepax wrote:
Was also considering if it would be worth adding an additional snd_soc_dapm_dsp id? That could sit between mixers and pgas, but I can't really see any obvious issue with treating the DSP as a mixer and it is a much simpler change. Although I am open to writing the other change if it is preferred?
One of the issues here was trying to ensure that the DSP started up with its inputs stable so noise from them starting didn't propagage into the algorithm and confuse it. The expecation with putting it as a PGA was that it would start with the outputs mute and do a digital unmute to bring them up. Since everything is digital this should all be more robust than it would be for analogue.
Muting the output is a little tricky though as a graph walk will be required to determine which output was connected, unless you have any handy ideas I have not spotted? I will start having a look to see what could be done on the muting front.
Thanks, Charles