[alsa-devel] [PATCH] ASoC: dapm: Fix race condition in widgets power list creation

Peter Ujfalusi peter.ujfalusi at nokia.com
Tue Jan 18 13:08:51 CET 2011

Resend, since alsa-devel address was mistyped ;)

On 01/18/11 13:39, ext Mark Brown wrote:
> > I *suspect* that we're in a similar case and either the locking has been
> > broken by the multi-component stuff or there's other cases that need
> > protection, probably the jack detection code.
The snd_soc_dapm_sync is just a wrapper for dapm_power_widgets, right?
It (snd_soc_dapm_sync) is used in soc-core:soc_post_component_init.
But there is no need for it, since the snd_soc_dapm_new_widgets will
call dapm_power_widgets at the end. so we can remove the
snd_soc_dapm_sync from there.
For the rest:
I would replace the snd_soc_dapm_sync calls in soc-dapm.c with
dapm_power_widgets(dapm, SND_SOC_DAPM_STREAM_NOP); calls.
Modify the snd_soc_dapm_sync to use the codec->mutex around the
dapm_power_widgets call.
In that way I think all race conditions going to be covered without
adding new mutex.

What do you think?
I can make a patch...


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