On Thu, 2010-11-04 at 10:16 +0200, Peter Ujfalusi wrote: > dapm_power_widgets can be called from different context. > When two calls are happening at the same time both will > try to change states/lists. This can lead to kernel crash. > > A simple way to reproduce the problem: > > while [ "1" = "1" ] ; do > amixer sset -Dhw:0 -q 'Mixer for loopback' on > amixer sset -Dhw:0 -q 'Mixer for loopback' off > done & > > while [ "1" = "1" ] ; do > aplay -Dplughw:0 -fdat -d 3 /dev/urandom > echo "Playback finished" > sleep 6 > done & > > Add new card level mutex (dpw_mutex) to protect the > dapm_power_widgets from race. > The exisiting card->mutex can not be used for this purpose, > since it has been taken in probe time in the > snd_soc_instantiate_card function. Through probe calls from > this function eventually dapm_power_widgets will be called, > which will lead to dead lock. > > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxx> Acked-by: Liam Girdwood <lrg@xxxxxxxxxxxxxxx> -- Freelance Developer, SlimLogic Ltd ASoC and Voltage Regulator Maintainer. http://www.slimlogic.co.uk _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
