linux-kernel - Re: [PATCH 1/2] ASoC: codecs: Use component driver suspend/resume

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Message-ID: <70362ac1-244b-43c5-97cb-ebe8f5b90c3f@tuxon.dev>
Date: Wed, 29 Oct 2025 17:22:26 +0200
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Mark Brown <broonie@...nel.org>
Cc: support.opensource@...semi.com, lgirdwood@...il.com, perex@...ex.cz,
 tiwai@...e.com, biju.das.jz@...renesas.com,
 prabhakar.mahadev-lad.rj@...renesas.com, linux-sound@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] ASoC: codecs: Use component driver suspend/resume

Hi, Mark,

On 10/29/25 16:37, Mark Brown wrote:
> On Wed, Oct 29, 2025 at 04:11:33PM +0200, Claudiu wrote:
> 
>> Since snd_soc_suspend() is invoked through snd_soc_pm_ops->suspend(),
>> and snd_soc_pm_ops is associated with the soc_driver (defined in
>> sound/soc/soc-core.c), and there is no parent-child relationship between
>> the soc_driver and the DA7213 codec driver, the power management subsystem
>> does not enforce a specific suspend/resume order between the DA7213 driver
>> and the soc_driver.
> 
> The theory here is that the power management core uses the device
> instantiation order for both suspend and resume (reversed on suspend) so
> the fact that we use probe deferral to make sure that the card
> components are ready should ensure that the card suspends before
> anything in the card.  If that is no longer the case then we need to
> ensure that all drivers have system PM ops which trigger the card, this
> won't be a driver specific issue.

I also saw the behavior described in this commit with the rz-ssi.c driver as 
well. The fix there was commit c1b0f5183a44 ("ASoC: renesas: rz-ssi: Use 
NOIRQ_SYSTEM_SLEEP_PM_OPS()").

In case of this this codec, I saw the code in da7213_runtime_resume() and 
soc_resume_deferred() racing each other on system resume.

> 
>>   static int da7213_runtime_resume(struct device *dev)
>>   {
>>   	struct da7213_priv *da7213 = dev_get_drvdata(dev);
>> -	int ret;
>>   
>> -	ret = regulator_bulk_enable(DA7213_NUM_SUPPLIES, da7213->supplies);
>> -	if (ret < 0)
>> -		return ret;
>> -	regcache_cache_only(da7213->regmap, false);
>> -	return regcache_sync(da7213->regmap);
>> +	return regulator_bulk_enable(DA7213_NUM_SUPPLIES, da7213->supplies);
>>   }
> 
> This seems obviously buggy, we just power on the device and don't sync
> the register state.  

You're right! I'll revisit this.

> If the device actually lost power during a runtime
> suspend then we'll end up having a bad time.  There was also no mention
> of runtime PM in the patch description...

I had no issues with runtime PM, but only with suspend to RAM, when this 
function was called though
struct dev_pm_ops::resume = pm_runtime_force_resume().

Would keeping the regcache_cache_only() + regcache_sync() here along with 
populating the struct snd_soc_component_driver::{suspend, resume} be an 
acceptable solution for you? I think that will work as well.

Thank you for your review,
Claudiu