On 04/09/2015 10:45 AM, Nicolin Chen wrote:
On Thu, Apr 09, 2015 at 10:29:39AM +0200, Lars-Peter Clausen wrote:
On 04/09/2015 10:22 AM, Nicolin Chen wrote:
On Thu, Apr 09, 2015 at 09:39:09AM +0200, Lars-Peter Clausen wrote:
The whole thing is a bit confusing. The message you get is what you'd get if the 'dapm' sub-directory in the card debugfs directory can not be created. One of the few reasons why it would fail is if it already existed, but we should never register two dapm contexts for the card, so that's a bit strange. One of the few reasons I can imagine this could happen is if the parent directory could not be created and now we try to create multiple dapm directories at the top-level.
Try to do some more debugging and see why and where exactly things go wrong. Can you also try this:
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index b6f8820..7810262 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -1898,6 +1898,11 @@ { struct dentry *d;
- if (!parent) {
dev_warn(dapm->dev, "No debugfs parent!\n");I tried, yes, the parent is NULL. And I did a little tracing and found that the card->debugfs_root, which is NULL, should be initialized in the soc_init_card_debugfs() while snd_soc_dapm_debugfs_init() seems to access this card->debugfs_root before calling soc_init_card_debugfs().
I think I must have missed something over here....
Looks like this is the culprit: http://git.kernel.org/cgit/linux/kernel/git/broonie/sound.git/commit/?h=for-...
I think this patch didn't move the snd_init_card_debugfs() backwards. It just wrapped the call at the end of snd_soc_instantiate_card().
Previously it was called before snd_soc_instantiate_card() and there is a lot of things inside snd_soc_instantiate_card() that expect the card debugfs directory to exist. So those now all end up at the top-level.
But the snd_soc_dapm_debugfs_init() call that's going to access the card->debugfs_root was put before the snd_init_card_debugfs() at the first place....
I'm not sure if this could be a fix but the warning is actually gone:
There is more stuff that expects the directory to exist in snd_soc_instantiate_card() so we need to move soc_init_card_debugfs() further up. See the patch I just sent.
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 2801578..0412795 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -1560,10 +1560,6 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card) card->dapm.card = card; list_add(&card->dapm.list, &card->dapm_list);
-#ifdef CONFIG_DEBUG_FS
- snd_soc_dapm_debugfs_init(&card->dapm, card->debugfs_card_root);
-#endif
- #ifdef CONFIG_PM_SLEEP /* deferred resume work */ INIT_WORK(&card->deferred_resume_work, soc_resume_deferred);
@@ -1686,6 +1682,10 @@ static int snd_soc_instantiate_card(struct snd_soc_card *card)
soc_init_card_debugfs(card);
+#ifdef CONFIG_DEBUG_FS
- snd_soc_dapm_debugfs_init(&card->dapm, card->debugfs_card_root);
+#endif
return 0;
probe_aux_dev_err: