linux-kernel - Re: [PATCH 3/4] ASoC: amd: acp: Add machine driver that enables sound for systems with a ES8336 codec

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Message-ID: <87zg2pxtog.fsf@mutex.one>
Date:   Fri, 18 Aug 2023 00:09:19 +0300
From:   Marian Postevca <posteuca@...ex.one>
To:     Mark Brown <broonie@...nel.org>
Cc:     沈一超 <zhuning0077@...il.com>,
        yangxiaohua <yangxiaohua@...rest-semi.com>,
        Zhu Ning <zhuning@...rest-semi.com>,
        Takashi Iwai <tiwai@...e.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>, linux-kernel@...r.kernel.org,
        alsa-devel@...a-project.org
Subject: Re: [PATCH 3/4] ASoC: amd: acp: Add machine driver that enables
 sound for systems with a ES8336 codec

Sorry for taking so long to look into this.
I think I understand why sound doesn't work if suspending with
headphones inserted.
When the jack is inserted, function
es8316_enable_micbias_for_mic_gnd_short_detect() is called and 3 pins
are enabled: Bias, Analog power, Mic Bias.

Since these 3 are supplies, the loop for_each_card_widgets() in
dapm_power_widgets() will always force the target_bias_level to be
SND_SOC_BIAS_STANDBY. So the codec component will never enter
SND_SOC_BIAS_OFF bias level.

When a suspend happens (with the headphones inserted) in
snd_soc_suspend(), in the for_each_rtd_components() loop, since the
bias level is SND_SOC_BIAS_STANDBY and dapm->idle_bias_off is true the
codec's suspend/resume functions are not called. Because of this the
codec stops running correctly.

Now I'm not sure what a proper fix would be. Enabling idle_bias_on in
struct snd_soc_component_driver fixes this issue. Would enabling
this option have any unwanted side effects?