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[ALSA] snd-dummy - improved timing, silence on prepare 

Signed-off-by: Ahmet İnan <ainan <at> mathematik.uni-freiburg.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Ahmet İnan 2008-02-21 07:55:30 +01:00 committed by Takashi Iwai
parent 03d7ca177f
commit 53463a8302
1 changed files with 15 additions and 11 deletions
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26
sound/drivers/dummy.c
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@ -181,10 +181,10 @@ struct snd_dummy_pcm {
struct snd_dummy *dummy;
spinlock_t lock;
struct timer_list timer;
unsigned int pcm_size;
unsigned int pcm_count;
unsigned int pcm_buffer_size;
unsigned int pcm_period_size;
unsigned int pcm_bps; /* bytes per second */
unsigned int pcm_jiffie; /* bytes per one jiffie */
unsigned int pcm_hz; /* HZ */
unsigned int pcm_irq_pos; /* IRQ position */
unsigned int pcm_buf_pos; /* position in buffer */
struct snd_pcm_substream *substream;
@ -238,11 +238,15 @@ static int snd_card_dummy_pcm_prepare(struct snd_pcm_substream *substream)
if (bps <= 0)
return -EINVAL;
dpcm->pcm_bps = bps;
dpcm->pcm_jiffie = bps / HZ;
dpcm->pcm_size = snd_pcm_lib_buffer_bytes(substream);
dpcm->pcm_count = snd_pcm_lib_period_bytes(substream);
dpcm->pcm_hz = HZ;
dpcm->pcm_buffer_size = snd_pcm_lib_buffer_bytes(substream);
dpcm->pcm_period_size = snd_pcm_lib_period_bytes(substream);
dpcm->pcm_irq_pos = 0;
dpcm->pcm_buf_pos = 0;
snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
bytes_to_samples(runtime, runtime->dma_bytes));
return 0;
}
@ -254,11 +258,11 @@ static void snd_card_dummy_pcm_timer_function(unsigned long data)
spin_lock_irqsave(&dpcm->lock, flags);
dpcm->timer.expires = 1 + jiffies;
add_timer(&dpcm->timer);
dpcm->pcm_irq_pos += dpcm->pcm_jiffie;
dpcm->pcm_buf_pos += dpcm->pcm_jiffie;
dpcm->pcm_buf_pos %= dpcm->pcm_size;
if (dpcm->pcm_irq_pos >= dpcm->pcm_count) {
dpcm->pcm_irq_pos %= dpcm->pcm_count;
dpcm->pcm_irq_pos += dpcm->pcm_bps;
if (dpcm->pcm_irq_pos >= dpcm->pcm_period_size * dpcm->pcm_hz) {
dpcm->pcm_irq_pos %= dpcm->pcm_period_size * dpcm->pcm_hz;
dpcm->pcm_buf_pos += dpcm->pcm_period_size;
dpcm->pcm_buf_pos %= dpcm->pcm_buffer_size;
spin_unlock_irqrestore(&dpcm->lock, flags);
snd_pcm_period_elapsed(dpcm->substream);
} else