[alsa-devel] [PATCH 3/3] ASoC: core: remove support for card rebind using component framework

[Srinivas Kandagatla]

DRM based audio components get registered inside the component framework
bind callback. However component framework has a big mutex lock taken for
every call to component_add, component_del and bind, unbind callbacks.

This can lead to deadlock situation if we are trying to add new/remove
component within a bind/unbind callbacks. Which is what was happening
with bcm2837 rpi 3.

Revert this change till we sort out the mutex issue.

Reported-by: Guillaume Tucker <guillaume.tucker at collabora.com>
Reported-by: Stefan Wahren <stefan.wahren at i2se.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
---
 include/sound/soc.h  |  7 ------
 sound/soc/soc-core.c | 62 ----------------------------------------------------
 2 files changed, 69 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index ace474e8649e..41cec42fb456 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -17,7 +17,6 @@
 #include <linux/workqueue.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
-#include <linux/component.h>
 #include <linux/regmap.h>
 #include <linux/log2.h>
 #include <sound/core.h>
@@ -1091,12 +1090,6 @@ struct snd_soc_card {
 
 	struct work_struct deferred_resume_work;
 
-	/* component framework related */
-	bool components_added;
-	/* set in machine driver to enable/disable auto re-binding */
-	bool auto_bind;
-	struct component_match *match;
-
 	/* lists of probed devices belonging to this card */
 	struct list_head component_dev_list;
 
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 81b27923303d..82eb3868be67 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -279,28 +279,11 @@ static inline void snd_soc_debugfs_exit(void)
 
 #endif
 
-static int snd_soc_card_comp_compare(struct device *dev, void *data)
-{
-	struct snd_soc_component *component;
-
-	lockdep_assert_held(&client_mutex);
-	list_for_each_entry(component, &component_list, list) {
-		if (dev == component->dev) {
-			if (!strcmp(component->name, data))
-				return 1;
-			break;
-		}
-	}
-
-	return 0;
-}
-
 static int snd_soc_rtdcom_add(struct snd_soc_pcm_runtime *rtd,
 			      struct snd_soc_component *component)
 {
 	struct snd_soc_rtdcom_list *rtdcom;
 	struct snd_soc_rtdcom_list *new_rtdcom;
-	char *cname;
 
 	for_each_rtdcom(rtd, rtdcom) {
 		/* already connected */
@@ -317,13 +300,6 @@ static int snd_soc_rtdcom_add(struct snd_soc_pcm_runtime *rtd,
 
 	list_add_tail(&new_rtdcom->list, &rtd->component_list);
 
-	if (rtd->card->auto_bind && !rtd->card->components_added) {
-		cname = devm_kasprintf(rtd->card->dev, GFP_KERNEL,
-				       "%s", component->name);
-		component_match_add(rtd->card->dev, &rtd->card->match,
-				    snd_soc_card_comp_compare, cname);
-	}
-
 	return 0;
 }
 
@@ -859,25 +835,6 @@ static bool soc_is_dai_link_bound(struct snd_soc_card *card,
 	return false;
 }
 
-static int snd_soc_card_comp_bind(struct device *dev)
-{
-	struct snd_soc_card *card = dev_get_drvdata(dev);
-
-	if (card->instantiated)
-		return 0;
-
-	return snd_soc_register_card(card);
-}
-
-static void snd_soc_card_comp_unbind(struct device *dev)
-{
-}
-
-static const struct component_master_ops snd_soc_card_comp_ops = {
-	.bind = snd_soc_card_comp_bind,
-	.unbind = snd_soc_card_comp_unbind,
-};
-
 static int soc_bind_dai_link(struct snd_soc_card *card,
 	struct snd_soc_dai_link *dai_link)
 {
@@ -2169,12 +2126,6 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
 
 	card->instantiated = 1;
 	snd_soc_dapm_sync(&card->dapm);
-	if (card->auto_bind && !card->components_added) {
-		component_master_add_with_match(card->dev,
-						&snd_soc_card_comp_ops,
-						card->match);
-		card->components_added = true;
-	}
 	mutex_unlock(&card->mutex);
 	mutex_unlock(&client_mutex);
 
@@ -2820,9 +2771,6 @@ int snd_soc_unregister_card(struct snd_soc_card *card)
 		dev_dbg(card->dev, "ASoC: Unregistered card '%s'\n", card->name);
 	}
 
-	if (!card->auto_bind && card->components_added)
-		component_master_del(card->dev, &snd_soc_card_comp_ops);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_soc_unregister_card);
@@ -3235,17 +3183,8 @@ int snd_soc_add_component(struct device *dev,
 
 	snd_soc_component_add(component);
 
-	ret = component_add(dev, NULL);
-	if (ret < 0) {
-		dev_err(dev, "ASoC: Failed to add Component: %d\n", ret);
-		goto err_comp;
-	}
-
 	return 0;
 
-err_comp:
-	soc_remove_component(component);
-	snd_soc_unregister_dais(component);
 err_cleanup:
 	snd_soc_component_cleanup(component);
 err_free:
@@ -3293,7 +3232,6 @@ static int __snd_soc_unregister_component(struct device *dev)
 	mutex_unlock(&client_mutex);
 
 	if (found) {
-		component_del(dev, NULL);
 		snd_soc_component_cleanup(component);
 	}
 
-- 
2.16.2