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Date:   Wed, 25 Oct 2023 09:57:12 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     perex@...ex.cz, tiwai@...e.com, lgirdwood@...il.com,
        linux-kernel@...r.kernel.org, alsa-devel@...a-project.org,
        johan+linaro@...nel.org, steev@...i.org,
        dmitry.baryshkov@...aro.org,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH 3/4] ASoC: codecs: wsa883x: mute/unmute PA in correct
 sequence

Hi Mark,

On Fri, Mar 24, 2023 at 06:44:40AM +0000, Srinivas Kandagatla wrote:
> On 23/03/2023 17:07, Mark Brown wrote:
> > On Thu, Mar 23, 2023 at 04:44:02PM +0000, Srinivas Kandagatla wrote:
> >> In the current setup the PA is left unmuted even when the
> >> Soundwire ports are not started streaming. This can lead to click
> >> and pop sounds during start.
> >> There is a same issue in the reverse order where in the PA is
> >> left unmute even after the data stream is stopped, the time
> >> between data stream stopping and port closing is long enough
> >> to accumulate DC on the line resulting in Click/Pop noise
> >> during end of stream.
> > 
> > Wow, that hardware sounds *super* fragile.
> > 
> >> Moving the mute/unmute to trigger stop/start respectively seems to
> >> help a lot with this Click/Pop issues reported on this Codec.
> > 
> >> +static int wsa883x_trigger(struct snd_pcm_substream *s, int cmd,
> >> +			   struct snd_soc_dai *dai)
> >> +{
> >> +	switch (cmd) {
> >> +	case SNDRV_PCM_TRIGGER_START:
> >> +	case SNDRV_PCM_TRIGGER_RESUME:
> >> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> >> +		wsa883x_digital_mute(dai, false, 0);
> >> +		break;
> > 
> >>   static const struct snd_soc_dai_ops wsa883x_dai_ops = {
> >> +	.startup = wsa883x_startup,
> >>   	.hw_params = wsa883x_hw_params,
> >>   	.hw_free = wsa883x_hw_free,
> >> -	.mute_stream = wsa883x_digital_mute,
> >> +	.trigger = wsa883x_trigger,

> > This feels like we should be doing it at the framework level, either
> > tightening up where the mute happens in general or having some option
> > that devices can select if they really need it.

> That makes more sense, I can give that a try.

I understand Srini has looked at this but has not yet been able to come
up with a generic implementation. Would it be possible to merge the two
codec fixes as an interim workaround for 6.7?

Without the wsa883x patch there's a loud crackling scary noise when
starting a stream on the Lenovo ThinkPad X13s which users will hit now
that they can run mainline on this machine.

	https://lore.kernel.org/lkml/20230323164403.6654-4-srinivas.kandagatla@linaro.org/

I've been using this one myself for the past seven months without any
issues (even if there's still a faint click when stopping a stream):

Tested-by: Johan Hovold <johan+linaro@...nel.org>

Getting this backported at least to 6.5 where sound support for the X13s
was added would be great too.

Johan

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