diff options
| -rw-r--r-- | sound/drivers/dummy.c | 78 |
1 files changed, 43 insertions, 35 deletions
diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c index f387d53e5039..0a798bde0d03 100644 --- a/sound/drivers/dummy.c +++ b/sound/drivers/dummy.c @@ -205,21 +205,43 @@ struct snd_dummy { struct dummy_systimer_pcm { spinlock_t lock; struct timer_list timer; - unsigned int pcm_buffer_size; - unsigned int pcm_period_size; - unsigned int pcm_bps; /* bytes per second */ - unsigned int pcm_hz; /* HZ */ - unsigned int pcm_irq_pos; /* IRQ position */ - unsigned int pcm_buf_pos; /* position in buffer */ + unsigned long base_time; + unsigned int frac_pos; /* fractional sample position (based HZ) */ + unsigned int frac_buffer_size; /* buffer_size * HZ */ + unsigned int frac_period_size; /* period_size * HZ */ + unsigned int rate; 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; + add_timer(&dpcm->timer); +} + +static void dummy_systimer_update(struct dummy_systimer_pcm *dpcm) +{ + unsigned long delta; + + delta = jiffies - dpcm->base_time; + if (!delta) + return; + dpcm->base_time = jiffies; + dpcm->frac_pos += delta * dpcm->rate; + while (dpcm->frac_pos >= dpcm->frac_buffer_size) + dpcm->frac_pos -= dpcm->frac_buffer_size; +} + static int dummy_systimer_start(struct snd_pcm_substream *substream) { struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; spin_lock(&dpcm->lock); - dpcm->timer.expires = 1 + jiffies; - add_timer(&dpcm->timer); + dpcm->base_time = jiffies; + dummy_systimer_rearm(dpcm); spin_unlock(&dpcm->lock); return 0; } @@ -237,20 +259,11 @@ static int dummy_systimer_prepare(struct snd_pcm_substream *substream) { struct snd_pcm_runtime *runtime = substream->runtime; struct dummy_systimer_pcm *dpcm = runtime->private_data; - int bps; - bps = snd_pcm_format_width(runtime->format) * runtime->rate * - runtime->channels / 8; - - if (bps <= 0) - return -EINVAL; - - dpcm->pcm_bps = bps; - 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; + dpcm->frac_pos = 0; + dpcm->rate = runtime->rate; + dpcm->frac_buffer_size = runtime->buffer_size * HZ; + dpcm->frac_period_size = runtime->period_size * HZ; return 0; } @@ -261,26 +274,21 @@ static void dummy_systimer_callback(unsigned long data) unsigned long flags; spin_lock_irqsave(&dpcm->lock, flags); - dpcm->timer.expires = 1 + jiffies; - add_timer(&dpcm->timer); - dpcm->pcm_irq_pos += dpcm->pcm_bps; - dpcm->pcm_buf_pos += dpcm->pcm_bps; - dpcm->pcm_buf_pos %= dpcm->pcm_buffer_size * dpcm->pcm_hz; - if (dpcm->pcm_irq_pos >= dpcm->pcm_period_size * dpcm->pcm_hz) { - dpcm->pcm_irq_pos %= dpcm->pcm_period_size * dpcm->pcm_hz; - spin_unlock_irqrestore(&dpcm->lock, flags); - snd_pcm_period_elapsed(dpcm->substream); - } else - spin_unlock_irqrestore(&dpcm->lock, flags); + dummy_systimer_update(dpcm); + dummy_systimer_rearm(dpcm); + spin_unlock_irqrestore(&dpcm->lock, flags); + snd_pcm_period_elapsed(dpcm->substream); } static snd_pcm_uframes_t dummy_systimer_pointer(struct snd_pcm_substream *substream) { - struct snd_pcm_runtime *runtime = substream->runtime; - struct dummy_systimer_pcm *dpcm = runtime->private_data; + struct dummy_systimer_pcm *dpcm = substream->runtime->private_data; - return bytes_to_frames(runtime, dpcm->pcm_buf_pos / dpcm->pcm_hz); + spin_lock(&dpcm->lock); + dummy_systimer_update(dpcm); + spin_unlock(&dpcm->lock); + return dpcm->frac_pos / HZ; } static int dummy_systimer_create(struct snd_pcm_substream *substream) |