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

From: Srinivas Kandagatla
Date: Thu Aug 02 2018 - 12:04:50 EST


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@xxxxxxxxxxxxx>
Reported-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
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