[alsa-devel] [PATCH 4/4] ASoC: soc-core: call snd_soc_remove_card() when component del

[Takashi Iwai]

At Mon, 9 Feb 2015 08:52:49 +0000,
Kuninori Morimoto wrote:
> 
> From: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> 
> ASoC devices are organized as CPU-CARD-CODEC. Then, CPU/CODEC
> are based on component structure. Now, each CARD device knows
> connected component. But CARD doesn't notice if connected component
> was removed when user called rmmod or unbind in current implementation.
> Thus, CARD which lost some components still exist in system.
> And then, ALSA sound card will have some problem if user used this CARD
> in such timing. This patch temporarily removes CARD from system
> if connected component was removed, and re-add it if some component
> was added.
> 
> Reported-by: Nguyen Viet Dung <nv-dung at jinso.co.jp>
> Reported-by: Bui Duc Phuc <bd-phuc at jinso.co.jp>
> Reported-by: Cao Minh Hiep <cm-hiep at jinso.co.jp>
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> ---
>  include/sound/soc.h  |    1 +
>  sound/soc/soc-core.c |   26 ++++++++++++++++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/include/sound/soc.h b/include/sound/soc.h
> index b4fca9a..a90eff4 100644
> --- a/include/sound/soc.h
> +++ b/include/sound/soc.h
> @@ -1083,6 +1083,7 @@ struct snd_soc_card {
>  	struct list_head paths;
>  	struct list_head dapm_list;
>  	struct list_head dapm_dirty;
> +	struct list_head unbinded_list;
>  
>  	/* Generic DAPM context for the card */
>  	struct snd_soc_dapm_context dapm;
> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
> index b7ab676..f8d5498 100644
> --- a/sound/soc/soc-core.c
> +++ b/sound/soc/soc-core.c
> @@ -56,6 +56,7 @@ static DEFINE_MUTEX(client_mutex);
>  static LIST_HEAD(platform_list);
>  static LIST_HEAD(codec_list);
>  static LIST_HEAD(component_list);
> +static LIST_HEAD(unbinded_card_list);
>  
>  /*
>   * This is a timeout to do a DAPM powerdown after a stream is closed().
> @@ -2406,6 +2407,10 @@ int snd_soc_unregister_card(struct snd_soc_card *card)
>  		dev_dbg(card->dev, "ASoC: Unregistered card '%s'\n", card->name);
>  	}
>  
> +	mutex_lock(&client_mutex);
> +	list_del(&card->unbinded_list);
> +	mutex_unlock(&client_mutex);
> +
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(snd_soc_unregister_card);
> @@ -2669,6 +2674,9 @@ EXPORT_SYMBOL_GPL(snd_soc_component_exit_regmap);
>  
>  static void snd_soc_component_add_unlocked(struct snd_soc_component *component)
>  {
> +	struct snd_soc_card *card, *_card;
> +	int ret;
> +
>  	if (!component->write && !component->read) {
>  		if (!component->regmap)
>  			component->regmap = dev_get_regmap(component->dev, NULL);
> @@ -2677,6 +2685,16 @@ static void snd_soc_component_add_unlocked(struct snd_soc_component *component)
>  	}
>  
>  	list_add(&component->list, &component_list);
> +
> +	/* re-add temporarily removed card if exist */
> +	list_for_each_entry_safe(card, _card, &unbinded_card_list,
> +				 unbinded_list) {
> +		ret = snd_soc_instantiate_card(card);
> +		if (ret < 0)
> +			continue;
> +
> +		list_del(&card->unbinded_list);
> +	}

[Cc'ed Lars-Peter]

This would instantiate a card even if it's irrelevant with the given
component?  If so, it looks fragile, and possibly racy, when there are
multiple cards.


thanks,

Takashi