The SNDRV_SEQ_IOCTL_SET_QUEUE_TEMPO ioctl sets the tempo and the ppq in a single call, while the current implementation updates each value one by one. This is a bit racy, and also suboptimal from the performance POV, as each call does re-acquire the lock and invokes the update of ALSA timer resolution.

This patch reorganizes the code slightly so that we change both the tempo and the ppq in a shot. The skew value can be put into the same lock, but this is rather a rarely used feature and completely independent from the temp/ppq (it's evaluated only in the interrupt), so it's left as it was.

Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/seq/seq_queue.c | 4 +--- sound/core/seq/seq_timer.c | 13 ++++++++----- sound/core/seq/seq_timer.h | 2 +- 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/sound/core/seq/seq_queue.c b/sound/core/seq/seq_queue.c index 79e0c5604ef8..0428e9061b47 100644 --- a/sound/core/seq/seq_queue.c +++ b/sound/core/seq/seq_queue.c @@ -497,9 +497,7 @@ int snd_seq_queue_timer_set_tempo(int queueid, int client, return -EPERM; }

- result = snd_seq_timer_set_tempo(q->timer, info->tempo); - if (result >= 0) - result = snd_seq_timer_set_ppq(q->timer, info->ppq); + result = snd_seq_timer_set_tempo_ppq(q->timer, info->tempo, info->ppq); if (result >= 0 && info->skew_base > 0) result = snd_seq_timer_set_skew(q->timer, info->skew_value, info->skew_base); diff --git a/sound/core/seq/seq_timer.c b/sound/core/seq/seq_timer.c index b80985fbc334..23167578231f 100644 --- a/sound/core/seq/seq_timer.c +++ b/sound/core/seq/seq_timer.c @@ -191,14 +191,15 @@ int snd_seq_timer_set_tempo(struct snd_seq_timer * tmr, int tempo) return 0; }

-/* set current ppq */ -int snd_seq_timer_set_ppq(struct snd_seq_timer * tmr, int ppq) +/* set current tempo and ppq in a shot */ +int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq) { + int changed; unsigned long flags;

if (snd_BUG_ON(!tmr)) return -EINVAL; - if (ppq <= 0) + if (tempo <= 0 || ppq <= 0) return -EINVAL; spin_lock_irqsave(&tmr->lock, flags); if (tmr->running && (ppq != tmr->ppq)) { @@ -208,9 +209,11 @@ int snd_seq_timer_set_ppq(struct snd_seq_timer * tmr, int ppq) pr_debug("ALSA: seq: cannot change ppq of a running timer\n"); return -EBUSY; } - + changed = (tempo != tmr->tempo) || (ppq != tmr->ppq); + tmr->tempo = tempo; tmr->ppq = ppq; - snd_seq_timer_set_tick_resolution(tmr); + if (changed) + snd_seq_timer_set_tick_resolution(tmr); spin_unlock_irqrestore(&tmr->lock, flags); return 0; } diff --git a/sound/core/seq/seq_timer.h b/sound/core/seq/seq_timer.h index 9506b661fe5b..62f390671096 100644 --- a/sound/core/seq/seq_timer.h +++ b/sound/core/seq/seq_timer.h @@ -131,7 +131,7 @@ int snd_seq_timer_stop(struct snd_seq_timer *tmr); int snd_seq_timer_start(struct snd_seq_timer *tmr); int snd_seq_timer_continue(struct snd_seq_timer *tmr); int snd_seq_timer_set_tempo(struct snd_seq_timer *tmr, int tempo); -int snd_seq_timer_set_ppq(struct snd_seq_timer *tmr, int ppq); +int snd_seq_timer_set_tempo_ppq(struct snd_seq_timer *tmr, int tempo, int ppq); int snd_seq_timer_set_position_tick(struct snd_seq_timer *tmr, snd_seq_tick_time_t position); int snd_seq_timer_set_position_time(struct snd_seq_timer *tmr, snd_seq_real_time_t position); int snd_seq_timer_set_skew(struct snd_seq_timer *tmr, unsigned int skew, unsigned int base);