The dmix plugin and co may trigger the resume for each instance in snd_pcm_direct_resume(). It means that the slave PCM gets resumed or re-prepared/started by each opened dmix stream, and this may end up with the doubly triggers even though the slave PCM has been already resumed by another dmix stream.
For avoiding this conflicts, check the slave PCM state and resume only when it's still in the suspended state. Meanwhile we keep the shadow state updated no matter whether the slave was triggered or not.
Signed-off-by: Takashi Iwai tiwai@suse.de --- src/pcm/pcm_direct.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/src/pcm/pcm_direct.c b/src/pcm/pcm_direct.c index e28738b0de96..ac082f1a73b2 100644 --- a/src/pcm/pcm_direct.c +++ b/src/pcm/pcm_direct.c @@ -841,6 +841,12 @@ int snd_pcm_direct_resume(snd_pcm_t *pcm) int err; snd_pcm_direct_semaphore_down(dmix, DIRECT_IPC_SEM_CLIENT); + /* resume only when the slave PCM is still in suspended state */ + if (snd_pcm_state(dmix->spcm) != SND_PCM_STATE_SUSPENDED) { + err = 0; + goto out; + } + err = snd_pcm_resume(dmix->spcm); if (err == -ENOSYS) { /* FIXME: error handling? */ @@ -848,6 +854,7 @@ int snd_pcm_direct_resume(snd_pcm_t *pcm) snd_pcm_start(dmix->spcm); err = 0; } + out: dmix->state = snd_pcm_state(dmix->spcm); snd_pcm_direct_semaphore_up(dmix, DIRECT_IPC_SEM_CLIENT); return err;