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@xxxxxxx>
---
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);
--
2.15.1
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