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pcm: dmix_rewind corrupts application pointer fix

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sometimes pulseaudio stops with the following assertion in libasound.so:
alsa-lib-1.0.29/src/pcm/pcm.c:2761:
snd_pcm_area_copy: Assertion `dst < src || dst >= src + bytes' failed.
Application pointer is handled properly, in cases of rewind operations.

Signed-off-by: Timo Wischer <twischer@de.adit-jv.com>
Signed-off-by: Ravikiran Polepalli <ravikiran_polepalli@mentor.com>
Signed-off-by: Mikhail Durnev <mikhail_durnev@mentor.com>
Signed-off-by: Mounesh Sutar <sutar.mounesh@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Timo Wischer 2017-02-17 12:45:36 +05:30 • committed by Takashi Iwai
parent 22eca6468b
commit df7694d80c
1 changed files with 23 additions and 10 deletions
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31
src/pcm/pcm_dmix.c
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@ -706,7 +706,7 @@ static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t f
{ {
snd_pcm_direct_t *dmix = pcm->private_data; snd_pcm_direct_t *dmix = pcm->private_data;
snd_pcm_uframes_t slave_appl_ptr, slave_size; snd_pcm_uframes_t slave_appl_ptr, slave_size;
snd_pcm_uframes_t appl_ptr, size, transfer, result; snd_pcm_uframes_t appl_ptr, size, transfer, result, frames_to_remix;
int err; int err;
const snd_pcm_channel_area_t *src_areas, *dst_areas; const snd_pcm_channel_area_t *src_areas, *dst_areas;
@ -717,6 +717,13 @@ static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t f
return err; return err;
} }
/* (appl_ptr - last_appl_ptr) indicates the frames which are not
* already mixed
* (last_appl_ptr - hw_ptr) indicates the frames which are already
* mixed but not played yet.
* So they can be remixed.
*/
if (dmix->last_appl_ptr < dmix->appl_ptr) if (dmix->last_appl_ptr < dmix->appl_ptr)
size = dmix->appl_ptr - dmix->last_appl_ptr; size = dmix->appl_ptr - dmix->last_appl_ptr;
else else
@ -729,6 +736,9 @@ static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t f
return size; return size;
result = size; result = size;
/* Always at this point last_appl_ptr == appl_ptr
* So (appl_ptr - hw_ptr) indicates the frames which can be remixed
*/
if (dmix->hw_ptr < dmix->appl_ptr) if (dmix->hw_ptr < dmix->appl_ptr)
size = dmix->appl_ptr - dmix->hw_ptr; size = dmix->appl_ptr - dmix->hw_ptr;
else else
@ -741,8 +751,11 @@ static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t f
slave_size = dmix->slave_appl_ptr + (pcm->boundary - dmix->slave_hw_ptr); slave_size = dmix->slave_appl_ptr + (pcm->boundary - dmix->slave_hw_ptr);
if (slave_size < size) if (slave_size < size)
size = slave_size; size = slave_size;
frames -= size;
result += size; /* frames which should be remixed will be saved
* to also backward the appl pointer on success
*/
frames_to_remix = size;
/* add sample areas here */ /* add sample areas here */
src_areas = snd_pcm_mmap_areas(pcm); src_areas = snd_pcm_mmap_areas(pcm);
@ -769,15 +782,15 @@ static snd_pcm_sframes_t snd_pcm_dmix_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t f
appl_ptr += transfer; appl_ptr += transfer;
appl_ptr %= pcm->buffer_size; appl_ptr %= pcm->buffer_size;
} }
dmix->last_appl_ptr -= frames;
dmix->last_appl_ptr %= pcm->boundary;
dmix->slave_appl_ptr -= frames;
dmix->slave_appl_ptr %= dmix->slave_boundary;
dmix_up_sem(dmix); dmix_up_sem(dmix);
snd_pcm_mmap_appl_backward(pcm, frames); snd_pcm_mmap_appl_backward(pcm, frames_to_remix);
result += frames_to_remix;
/* At this point last_appl_ptr and appl_ptr has to indicate the
* position of the first not mixed frame
*/
return result + frames; return result;
} }
static snd_pcm_sframes_t snd_pcm_dmix_forwardable(snd_pcm_t *pcm) static snd_pcm_sframes_t snd_pcm_dmix_forwardable(snd_pcm_t *pcm)