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ALSA: dummy - Fix the timer calculation in systimer mode

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Fix the expire-time calculation in the systimer mode when the buffer
size isn't aligned to the period size.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2009-09-04 08:45:11 +02:00
parent 30681bcf2b
commit b5d1078173
1 changed files with 21 additions and 8 deletions
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29
sound/drivers/dummy.c
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@ -207,19 +207,18 @@ struct dummy_systimer_pcm {
struct timer_list timer;
unsigned long base_time;
unsigned int frac_pos; /* fractional sample position (based HZ) */
unsigned int frac_period_rest;
unsigned int frac_buffer_size; /* buffer_size * HZ */
unsigned int frac_period_size; /* period_size * HZ */
unsigned int rate;
int elapsed;
struct snd_pcm_substream *substream;
};
static void dummy_systimer_rearm(struct dummy_systimer_pcm *dpcm)
{
unsigned long frac;
frac = dpcm->frac_pos % dpcm->frac_period_size;
dpcm->timer.expires = jiffies +
(dpcm->frac_period_size + dpcm->rate - 1) / dpcm->rate;
(dpcm->frac_period_rest + dpcm->rate - 1) / dpcm->rate;
add_timer(&dpcm->timer);
}
@ -230,10 +229,16 @@ static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm)
delta = jiffies - dpcm->base_time;
if (!delta)
return;
dpcm->base_time = jiffies;
dpcm->frac_pos += delta * dpcm->rate;
dpcm->base_time += delta;
delta *= dpcm->rate;
dpcm->frac_pos += delta;
while (dpcm->frac_pos >= dpcm->frac_buffer_size)
dpcm->frac_pos -= dpcm->frac_buffer_size;
while (dpcm->frac_period_rest <= delta) {
dpcm->elapsed++;
dpcm->frac_period_rest += dpcm->frac_period_size;
}
dpcm->frac_period_rest -= delta;
}
static int dummy_systimer_start(struct snd_pcm_substream *substream)
@ -264,6 +269,8 @@ static int dummy_systimer_prepare(struct snd_pcm_substream *substream)
dpcm->rate = runtime->rate;
dpcm->frac_buffer_size = runtime->buffer_size * HZ;
dpcm->frac_period_size = runtime->period_size * HZ;
dpcm->frac_period_rest = dpcm->frac_period_size;
dpcm->elapsed = 0;
return 0;
}
@ -272,23 +279,29 @@ static void dummy_systimer_callback(unsigned long data)
{
struct dummy_systimer_pcm *dpcm = (struct dummy_systimer_pcm *)data;
unsigned long flags;
int elapsed = 0;
spin_lock_irqsave(&dpcm->lock, flags);
dummy_systimer_update(dpcm);
dummy_systimer_rearm(dpcm);
elapsed = dpcm->elapsed;
dpcm->elapsed = 0;
spin_unlock_irqrestore(&dpcm->lock, flags);
snd_pcm_period_elapsed(dpcm->substream);
if (elapsed)
snd_pcm_period_elapsed(dpcm->substream);
}
static snd_pcm_uframes_t
dummy_systimer_pointer(struct snd_pcm_substream *substream)
{
struct dummy_systimer_pcm *dpcm = substream->runtime->private_data;
snd_pcm_uframes_t pos;
spin_lock(&dpcm->lock);
dummy_systimer_update(dpcm);
pos = dpcm->frac_pos / HZ;
spin_unlock(&dpcm->lock);
return dpcm->frac_pos / HZ;
return pos;
}
static int dummy_systimer_create(struct snd_pcm_substream *substream)