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-...