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

[claudiu beznea]

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