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Fix boundary overlap

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Fixed the possible bug with boundary overlap in dmix code.
This commit is contained in:
Takashi Iwai 2005-06-16 14:03:15 +00:00
parent ce67d5389b
commit 6c7f60f7a9
1 changed files with 16 additions and 4 deletions
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20
src/pcm/pcm_dmix.c
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@ -239,13 +239,20 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
{ {
snd_pcm_direct_t *dmix = pcm->private_data; snd_pcm_direct_t *dmix = pcm->private_data;
snd_pcm_uframes_t appl_ptr, slave_appl_ptr, slave_bsize; snd_pcm_uframes_t appl_ptr, slave_appl_ptr, slave_bsize;
snd_pcm_uframes_t size, slave_hw_ptr; snd_pcm_uframes_t size, slave_size, slave_hw_ptr;
const snd_pcm_channel_area_t *src_areas, *dst_areas; const snd_pcm_channel_area_t *src_areas, *dst_areas;
/* calculate the size to transfer */ /* calculate the size to transfer */
/* check the available size in the local buffer
* last_appl_ptr keeps the last updated position
*/
size = dmix->appl_ptr - dmix->last_appl_ptr; size = dmix->appl_ptr - dmix->last_appl_ptr;
if (! size) if (! size)
return; return;
if (size >= pcm->boundary / 2)
size = pcm->boundary - size;
/* check the available size in the slave PCM buffer */
slave_bsize = dmix->shmptr->s.buffer_size; slave_bsize = dmix->shmptr->s.buffer_size;
slave_hw_ptr = dmix->slave_hw_ptr; slave_hw_ptr = dmix->slave_hw_ptr;
/* don't write on the last active period - this area may be cleared /* don't write on the last active period - this area may be cleared
@ -253,12 +260,17 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
*/ */
slave_hw_ptr -= slave_hw_ptr % dmix->shmptr->s.period_size; slave_hw_ptr -= slave_hw_ptr % dmix->shmptr->s.period_size;
slave_hw_ptr += slave_bsize; slave_hw_ptr += slave_bsize;
if (dmix->slave_hw_ptr > dmix->slave_appl_ptr) if (slave_hw_ptr >= dmix->shmptr->s.boundary)
slave_hw_ptr -= dmix->shmptr->s.boundary; slave_hw_ptr -= dmix->shmptr->s.boundary;
if (dmix->slave_appl_ptr + size >= slave_hw_ptr) if (slave_hw_ptr < dmix->slave_appl_ptr)
size = slave_hw_ptr - dmix->slave_appl_ptr; slave_size = slave_hw_ptr + (dmix->shmptr->s.boundary - dmix->slave_appl_ptr);
else
slave_size = slave_hw_ptr - dmix->slave_appl_ptr;
if (slave_size < size)
size = slave_size;
if (! size) if (! size)
return; return;
/* add sample areas here */ /* add sample areas here */
src_areas = snd_pcm_mmap_areas(pcm); src_areas = snd_pcm_mmap_areas(pcm);
dst_areas = snd_pcm_mmap_areas(dmix->spcm); dst_areas = snd_pcm_mmap_areas(dmix->spcm);