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Commit 671ec859 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: seq: Process queue tempo/ppq change in a shot 



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: default avatarTakashi Iwai <tiwai@suse.de>
parent 4ea5553a

sound/core/seq/seq_queue.c

+1 −3
Original line number Diff line number Diff line
@@ -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);

sound/core/seq/seq_timer.c

+8 −5
Original line number Diff line number Diff line
@@ -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)) {
@@ -208,8 +209,10 @@ 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;

	if (changed)

		snd_seq_timer_set_tick_resolution(tmr);

	spin_unlock_irqrestore(&tmr->lock, flags);

	return 0;

sound/core/seq/seq_timer.h

+1 −1
Original line number Diff line number Diff line
@@ -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);