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Diffstat (limited to 'sound/drivers/dummy.c')
-rw-r--r--sound/drivers/dummy.c78
1 files changed, 43 insertions, 35 deletions
diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c
index f387d53e503..0a798bde0d0 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)