Re: [PATCH 02/15] ASoC: dapm: Add locked version of snd_soc_dapm_xxxx_pin functions

[Lars-Peter Clausen <lars@metafoo.de>]

[...]
> +int snd_soc_dapm_enable_pin_locked(struct snd_soc_dapm_context *dapm,
> +				   const char *pin)
> +{
> +	return snd_soc_dapm_set_pin(dapm, pin, 1);
> +}
> +EXPORT_SYMBOL_GPL(snd_soc_dapm_enable_pin_locked);
> +
> +/**
>    * snd_soc_dapm_enable_pin - enable pin.
>    * @dapm: DAPM context
>    * @pin: pin name
>    *
>    * Enables input/output pin and its parents or children widgets iff there is
>    * a valid audio route and active audio stream.
> + *
>    * NOTE: snd_soc_dapm_sync() needs to be called after this for DAPM to
>    * do any widget power switching.
>    */
>   int snd_soc_dapm_enable_pin(struct snd_soc_dapm_context *dapm, const char *pin)
>   {
> -	return snd_soc_dapm_set_pin(dapm, pin, 1);
> +	int ret;
> +
> +	mutex_lock_nested(&dapm->card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
> +
> +	ret = snd_soc_dapm_set_pin(dapm, pin, 1);
> +
> +	mutex_unlock(&dapm->card->dapm_mutex);
> +
> +	return ret;
>   }

Hm, this is a bit confusing. For other functions in ASoC when we have a pair 
of functions with the _locked suffix and without the one with _locked takes 
the lock, the other one doesn't. E.g. snd_soc_update_bits_locked. Here we do 
it the other way around.

- Lars