ASoC: dpcm: Make BE prepare possible in suspend state
authorKoro Chen <koro.chen@mediatek.com>
Wed, 28 Oct 2015 02:15:34 +0000 (10:15 +0800)
committerMark Brown <broonie@kernel.org>
Mon, 16 Nov 2015 10:04:04 +0000 (10:04 +0000)
commit95f444dc9371a3910179a9621c8b94f0f60f5f04
tree0b3b8157de28945330ac5f66cc381b221dcbe956
parent8005c49d9aea74d382f474ce11afbbc7d7130bec
ASoC: dpcm: Make BE prepare possible in suspend state

During suspend/resume, there is a flow that if a driver does not support
SNDRV_PCM_INFO_RESUME, it will fail at snd_pcm_resume(), and user space
can then issue SNDRV_PCM_IOCTL_PREPARE to let audio continue to play.

However, in dpcm_be_dai_prepare() it only allows BEs to be prepared
in state SND_SOC_DPCM_STATE_HW_PARAMS or SND_SOC_DPCM_STATE_STOP.
The BE state will then stay in SND_SOC_DPCM_STATE_SUSPEND, consequently
dpcm_be_dai_shutdown() is skipped in the end of playback and
be_substream->runtime is not cleared while this runtime is actually freed
by snd_pcm_detach_substream(). If another suspend comes, a NULL pointer
dereference will happen in snd_pcm_suspend() when accessing
BE substream's runtime.

Signed-off-by: Koro Chen <koro.chen@mediatek.com>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
sound/soc/soc-pcm.c