[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>

1 files changed, 15 insertions, 11 deletions

diff --git a/sound/drivers/dummy.c b/sound/drivers/dummy.c
index a240eaeb5c62..f67f65829f3e 100644
--- a/sound/drivers/dummy.c
+++ b/sound/drivers/dummy.c
@@ -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