Commit b5d10781 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: dummy - Fix the timer calculation in systimer mode 



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

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 30681bcf

sound/drivers/dummy.c

+21 −8
Original line number Diff line number Diff line
@@ -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;

}
@@ -272,11 +279,15 @@ 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);

	if (elapsed)

		snd_pcm_period_elapsed(dpcm->substream);

}
@@ -284,11 +295,13 @@ 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)