diff options
| author | Jaroslav Kysela <perex@perex.cz> | 2010-10-20 10:27:02 +0400 |
|---|---|---|
| committer | Jaroslav Kysela <perex@perex.cz> | 2010-10-20 11:35:38 +0400 |
| commit | dd04bb12d047a4d4461772093472a40dbe171e5f (patch) | |
| tree | ebbd1b742531f1a2033f11ee838f8d1ed62278be | |
| parent | e74670b6fdc37b15ebee11825849d8983e52a74a (diff) | |
| download | linux-dd04bb12d047a4d4461772093472a40dbe171e5f.tar.xz | |
ALSA: snd-aloop - fix locking issues (running flag updates)
On SMP machines, the cable->running update must be atomic, otherwise
stream is not started correctly sometimes.
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
| -rw-r--r-- | sound/drivers/aloop.c | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index 66786ea6f480..38e8351e935d 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -263,13 +263,17 @@ static int loopback_trigger(struct snd_pcm_substream *substream, int cmd) return err; dpcm->last_jiffies = jiffies; dpcm->pcm_rate_shift = 0; - loopback_timer_start(dpcm); + spin_lock(&cable->lock); cable->running |= (1 << substream->stream); + spin_unlock(&cable->lock); + loopback_timer_start(dpcm); if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) loopback_active_notify(dpcm); break; case SNDRV_PCM_TRIGGER_STOP: + spin_lock(&cable->lock); cable->running &= ~(1 << substream->stream); + spin_unlock(&cable->lock); loopback_timer_stop(dpcm); if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) loopback_active_notify(dpcm); @@ -454,28 +458,30 @@ static void loopback_bytepos_update(struct loopback_pcm *dpcm, } } -static void loopback_pos_update(struct loopback_cable *cable) +static unsigned int loopback_pos_update(struct loopback_cable *cable) { struct loopback_pcm *dpcm_play = cable->streams[SNDRV_PCM_STREAM_PLAYBACK]; struct loopback_pcm *dpcm_capt = cable->streams[SNDRV_PCM_STREAM_CAPTURE]; unsigned long delta_play = 0, delta_capt = 0; + unsigned int running; spin_lock(&cable->lock); - if (cable->running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { + running = cable->running; + if (running & (1 << SNDRV_PCM_STREAM_PLAYBACK)) { delta_play = jiffies - dpcm_play->last_jiffies; dpcm_play->last_jiffies += delta_play; } - if (cable->running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { + if (running & (1 << SNDRV_PCM_STREAM_CAPTURE)) { delta_capt = jiffies - dpcm_capt->last_jiffies; dpcm_capt->last_jiffies += delta_capt; } if (delta_play == 0 && delta_capt == 0) { spin_unlock(&cable->lock); - return; + return running; } if (delta_play > delta_capt) { @@ -490,27 +496,27 @@ static void loopback_pos_update(struct loopback_cable *cable) if (delta_play == 0 && delta_capt == 0) { spin_unlock(&cable->lock); - return; + return running; } /* note delta_capt == delta_play at this moment */ loopback_bytepos_update(dpcm_capt, delta_capt, BYTEPOS_UPDATE_COPY); loopback_bytepos_update(dpcm_play, delta_play, BYTEPOS_UPDATE_POSONLY); spin_unlock(&cable->lock); + return running; } static void loopback_timer_function(unsigned long data) { struct loopback_pcm *dpcm = (struct loopback_pcm *)data; - int stream; + unsigned int running; - loopback_pos_update(dpcm->cable); - stream = dpcm->substream->stream; - if (dpcm->cable->running & (1 << stream)) + running = loopback_pos_update(dpcm->cable); + if (running & (1 << dpcm->substream->stream)) { loopback_timer_start(dpcm); - if (dpcm->period_update_pending) { - dpcm->period_update_pending = 0; - if (dpcm->cable->running & (1 << stream)) + if (dpcm->period_update_pending) { + dpcm->period_update_pending = 0; snd_pcm_period_elapsed(dpcm->substream); + } } } |