Re: [PATCH v2] ASoC: cs35l56: Fix probe deadlock waiting for SoundWire enumeration

[Mark Brown <broonie@kernel.org>]

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On Thu, Aug 13, 2026 at 06:37:01PM +0100, Richard Fitzgerald wrote:
> Defer all the parts of cs35l56_component_probe() that require register
> access to a work item. This is to prevent a deadlock where
> cs35l56_component_probe() is waiting for init_completion to be signaled
> but is blocking the code that would signal it.

>  static void cs35l56_wait_dsp_ready(struct cs35l56_private *cs35l56)
>  {
>  	/* Wait for patching to complete */
> +	flush_work(&cs35l56->deferred_component_init_work);
>  	flush_work(&cs35l56->dsp_work);
>  }
>  

This can be called from asoc_sdw_cs_spk_rtd_init() when limiting the
volume, that's still synchronous while setting up the card - the main
Speaker Volume control uses cs35l56_dspwait_{get,put}_volsw() and when
we set up the volume limit we at least read the current volume.  The
deferred work will block on init_completion and error out if that times
out but init_completion is still signalled in the callback that's
blocked waiting for probe().

AFAICT we always try to limit the volume for these speakers?

I think the component registration needs to be moved out of probe into a
work item...

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