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pcm: ioplug: Transfer all available data

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The snd_pcm_mmap_begin() call returns the amount of contiguous data,
which is less than the total available if it wraps around the buffer
boundary.

If we don't handle this split we leave stale data in the buffer that
should have been overwritten, as well as unread data in the io_plugin
that gets transferred on a subsequent call at the wrong offset.

Signed-off-by: Rob Duncan <rduncan@teslamotors.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Rob Duncan 2018-07-16 16:35:23 -07:00 • committed by Takashi Iwai
parent b0fc685115
commit 1714332719
1 changed files with 13 additions and 1 deletions
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14
src/pcm/pcm_ioplug.c
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@ -716,6 +716,8 @@ static snd_pcm_sframes_t snd_pcm_ioplug_avail_update(snd_pcm_t *pcm)
snd_pcm_ioplug_hw_ptr_update(pcm);
if (io->data->state == SND_PCM_STATE_XRUN)
return -EPIPE;
avail = snd_pcm_mmap_avail(pcm);
if (pcm->stream == SND_PCM_STREAM_CAPTURE &&
pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED &&
pcm->access != SND_PCM_ACCESS_RW_NONINTERLEAVED) {
@ -728,9 +730,19 @@ static snd_pcm_sframes_t snd_pcm_ioplug_avail_update(snd_pcm_t *pcm)
result = io->data->callback->transfer(io->data, areas, offset, size);
if (result < 0)
return result;
/* If the available data doesn't fit in the
contiguous area at the end of the mmap we
must transfer the remaining data to the
beginning of the mmap. */
if (size < avail) {
result = io->data->callback->transfer(io->data, areas,
0, avail - size);
if (result < 0)
return result;
}
}
}
avail = snd_pcm_mmap_avail(pcm);
if (avail > io->avail_max)
io->avail_max = avail;
return (snd_pcm_sframes_t)avail;