[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>
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03d7ca177f
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@ -181,10 +181,10 @@ struct snd_dummy_pcm {
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struct snd_dummy *dummy;
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spinlock_t lock;
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struct timer_list timer;
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unsigned int pcm_size;
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unsigned int pcm_count;
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unsigned int pcm_buffer_size;
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unsigned int pcm_period_size;
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unsigned int pcm_bps; /* bytes per second */
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unsigned int pcm_jiffie; /* bytes per one jiffie */
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unsigned int pcm_hz; /* HZ */
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unsigned int pcm_irq_pos; /* IRQ position */
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unsigned int pcm_buf_pos; /* position in buffer */
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struct snd_pcm_substream *substream;
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@ -238,11 +238,15 @@ static int snd_card_dummy_pcm_prepare(struct snd_pcm_substream *substream)
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if (bps <= 0)
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return -EINVAL;
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dpcm->pcm_bps = bps;
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dpcm->pcm_jiffie = bps / HZ;
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dpcm->pcm_size = snd_pcm_lib_buffer_bytes(substream);
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dpcm->pcm_count = snd_pcm_lib_period_bytes(substream);
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dpcm->pcm_hz = HZ;
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dpcm->pcm_buffer_size = snd_pcm_lib_buffer_bytes(substream);
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dpcm->pcm_period_size = snd_pcm_lib_period_bytes(substream);
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dpcm->pcm_irq_pos = 0;
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dpcm->pcm_buf_pos = 0;
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snd_pcm_format_set_silence(runtime->format, runtime->dma_area,
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bytes_to_samples(runtime, runtime->dma_bytes));
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return 0;
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}
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@ -254,11 +258,11 @@ static void snd_card_dummy_pcm_timer_function(unsigned long data)
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spin_lock_irqsave(&dpcm->lock, flags);
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dpcm->timer.expires = 1 + jiffies;
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add_timer(&dpcm->timer);
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dpcm->pcm_irq_pos += dpcm->pcm_jiffie;
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dpcm->pcm_buf_pos += dpcm->pcm_jiffie;
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dpcm->pcm_buf_pos %= dpcm->pcm_size;
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if (dpcm->pcm_irq_pos >= dpcm->pcm_count) {
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dpcm->pcm_irq_pos %= dpcm->pcm_count;
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dpcm->pcm_irq_pos += dpcm->pcm_bps;
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if (dpcm->pcm_irq_pos >= dpcm->pcm_period_size * dpcm->pcm_hz) {
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dpcm->pcm_irq_pos %= dpcm->pcm_period_size * dpcm->pcm_hz;
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dpcm->pcm_buf_pos += dpcm->pcm_period_size;
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dpcm->pcm_buf_pos %= dpcm->pcm_buffer_size;
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spin_unlock_irqrestore(&dpcm->lock, flags);
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snd_pcm_period_elapsed(dpcm->substream);
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} else
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