RE: [alsa-devel] [PATCH] ASoC: eve: implement set_bias_level function for rt5514

From: Lu, Brent
Date: Fri Oct 25 2019 - 12:15:14 EST

> Can you clarify if the rt5514 needs the MCLK while it's doing the hotword
> detection?

No, running the detection does not raise the bias level so the set_bias_level
will not be called. The mclk is only turned on then off in mixer control's handler
(rt5514_dsp_voice_wake_up_put) when enabling the hotword detection.

> My point is really that this patch uses a card-level BIAS indication, and I'd like
> to make sure this does not interfere with the audio DSP being in D3 state.

The function checks the name of dapm so it would only react when rt5514's
bias level is changing. And also the idle_bias_off of the codec driver is true so
it's target_bias_level should not be overwritten in the dapm_power_widgets()
function. The behavior should be similar to the previous patch which is using
supply widget.