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ALSA: snd-aloop - fix issue in the timer start function

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In some circumstances (the rate shift value was changed), the irq_pos
value may be higher than the fraction value in the timer start function.
Check for it.

Also, to avoid value overflow, decrease maximum period size.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2010-10-14 21:46:12 +02:00
parent 838c364ff0
commit 0db7102305
1 changed files with 7 additions and 1 deletions
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8
sound/drivers/aloop.c
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@ -171,6 +171,10 @@ static void loopback_timer_start(struct loopback_pcm *dpcm)
dpcm->pcm_rate_shift = rate_shift;
dpcm->period_size_frac = frac_pos(dpcm, dpcm->pcm_period_size);
}
if (dpcm->period_size_frac <= dpcm->irq_pos) {
dpcm->irq_pos %= dpcm->period_size_frac;
dpcm->period_update_pending = 1;
}
tick = dpcm->period_size_frac - dpcm->irq_pos;
tick = (tick + dpcm->pcm_bps - 1) / dpcm->pcm_bps;
dpcm->timer.expires = jiffies + tick;
@ -531,7 +535,9 @@ static struct snd_pcm_hardware loopback_pcm_hardware =
.channels_max = 32,
.buffer_bytes_max = 2 * 1024 * 1024,
.period_bytes_min = 64,
.period_bytes_max = 2 * 1024 * 1024,
/* note check overflow in frac_pos() using pcm_rate_shift before
changing period_bytes_max value */
.period_bytes_max = 1024 * 1024,
.periods_min = 1,
.periods_max = 1024,
.fifo_size = 0,