linux-kernel - Re: [PATCH] ASoC: atmel: mchp-pdmc: Skip ALSA restoration if substream runtime is uninitialized

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Message-ID: <ZvJ_ZFpIiRpD_uzO@finisterre.sirena.org.uk>
Date: Tue, 24 Sep 2024 10:59:48 +0200
From: Mark Brown <broonie@...nel.org>
To: Andrei Simion <andrei.simion@...rochip.com>
Cc: claudiu.beznea@...on.dev, lgirdwood@...il.com, perex@...ex.cz,
	tiwai@...e.com, nicolas.ferre@...rochip.com,
	alexandre.belloni@...tlin.com, alsa-devel@...a-project.org,
	linux-sound@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: atmel: mchp-pdmc: Skip ALSA restoration if
 substream runtime is uninitialized

On Tue, Sep 24, 2024 at 11:12:38AM +0300, Andrei Simion wrote:

> Update the driver to prevent alsa-restore.service from failing when
> reading data from /var/lib/alsa/asound.state at boot. Ensure that the
> restoration of ALSA mixer configurations is skipped if substream->runtime
> is NULL.

> +++ b/sound/soc/atmel/mchp-pdmc.c
> @@ -302,6 +302,9 @@ static int mchp_pdmc_chmap_ctl_put(struct snd_kcontrol *kcontrol,
>  	if (!substream)
>  		return -ENODEV;
>  
> +	if (!substream->runtime)
> +		return 0; /* just for avoiding error from alsactl restore */
> +

This then means that control writes are just discarded which presumably
is going to upset things if they actually saved a value here.  Why is
that a good choice, rather than either fixing the race so the card
doesn't come up too early or removing the need for the runtime?

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