The available size calculation did not handle wraparound correctly. Also, the
underrun handling code confused slave_buffer_size with slave_boundary, causing
another integer overflow that results in too many samples being skipped.
Signed-off-by: Maarten Baert <maarten-baert@xxxxxxxxxxx>
---
src/pcm/pcm_dmix.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/src/pcm/pcm_dmix.c b/src/pcm/pcm_dmix.c
index 843fa316..b5fdb240 100644
--- a/src/pcm/pcm_dmix.c
+++ b/src/pcm/pcm_dmix.c
@@ -315,11 +315,12 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
/* check the available size in the local buffer
* last_appl_ptr keeps the last updated position
*/
- size = dmix->appl_ptr - dmix->last_appl_ptr;
+ if (dmix->appl_ptr >= dmix->last_appl_ptr)
+ size = dmix->appl_ptr - dmix->last_appl_ptr;
+ else
+ size = dmix->appl_ptr + (pcm->boundary - dmix->last_appl_ptr);
if (! size)
return;
- if (size >= pcm->boundary / 2)
- size = pcm->boundary - size;
/* the slave_app_ptr can be far behind the slave_hw_ptr */
/* reduce mixing and errors here - just skip not catched writes */
@@ -328,18 +329,19 @@ static void snd_pcm_dmix_sync_area(snd_pcm_t *pcm)
else
slave_size = dmix->slave_appl_ptr + (dmix->slave_boundary - dmix->slave_hw_ptr);
if (slave_size > dmix->slave_buffer_size) {
- transfer = dmix->slave_buffer_size - slave_size;
+ transfer = dmix->slave_boundary - slave_size;
if (transfer > size)
transfer = size;
dmix->last_appl_ptr += transfer;
dmix->last_appl_ptr %= pcm->boundary;
dmix->slave_appl_ptr += transfer;
dmix->slave_appl_ptr %= dmix->slave_boundary;
- size = dmix->appl_ptr - dmix->last_appl_ptr;
+ if (dmix->appl_ptr >= dmix->last_appl_ptr)
+ size = dmix->appl_ptr - dmix->last_appl_ptr;
+ else
+ size = dmix->appl_ptr + (pcm->boundary - dmix->last_appl_ptr);
if (! size)
return;
- if (size >= pcm->boundary / 2)
- size = pcm->boundary - size;
}
/* check the available size in the slave PCM buffer */
--
2.26.2
