[alsa-devel] [PATCH 4/5 v4] ASoC: soc-core: call snd_soc_remove_card() when component del

[Kuninori Morimoto]

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 components. But CARD doesn't notice if connected component
was removed when user used 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>
---
v3 -> v4

 - initialize unbinded_list
 - used mutex_lock in snd_soc_unregister_card()
 - check component->probed in snd_soc_component_del_unlocked()

 include/sound/soc.h  |    1 +
 sound/soc/soc-core.c |   27 +++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index ac8b333..a9272a4 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1084,6 +1084,7 @@ 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 5d85b5b..f04e97d 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().
@@ -2379,6 +2380,7 @@ int snd_soc_register_card(struct snd_soc_card *card)
 		card->rtd_aux[i].card = card;
 
 	INIT_LIST_HEAD(&card->dapm_dirty);
+	INIT_LIST_HEAD(&card->unbinded_list);
 	card->instantiated = 0;
 	mutex_init(&card->mutex);
 	mutex_init(&card->dapm_mutex);
@@ -2406,6 +2408,10 @@ 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_init(&card->unbinded_list);
+	mutex_unlock(&client_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_soc_unregister_card);
@@ -2669,6 +2675,9 @@ 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 +2686,16 @@ 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_init(&card->unbinded_list);
+	}
 }
 
 static void snd_soc_component_add(struct snd_soc_component *component)
@@ -2694,7 +2713,15 @@ static void snd_soc_component_cleanup(struct snd_soc_component *component)
 
 static void snd_soc_component_del_unlocked(struct snd_soc_component *component)
 {
+	struct snd_soc_card *card = component->card;
+
 	list_del(&component->list);
+
+	/* card is removed temporarily */
+	if (component->probed && card->instantiated) {
+		list_add(&card->unbinded_list, &unbinded_card_list);
+		snd_soc_remove_card(card);
+	}
 }
 
 static void snd_soc_component_del(struct snd_soc_component *component)
-- 
1.7.9.5