This patch improves recovering from underruns, and prevents hangs inside snd_pcm_write* and snd_pcm_read* due to snd_pcm_avail* returning too low values. It especially helps low latency situations.

Signed-off-by: David Henningsson diwic@ubuntu.com --- pulse/pcm_pulse.c | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-)

Index: alsa-plugins-1.0.22/pulse/pcm_pulse.c =================================================================== --- alsa-plugins-1.0.22.orig/pulse/pcm_pulse.c 2010-02-28 17:12:02.000000000 -0500 +++ alsa-plugins-1.0.22/pulse/pcm_pulse.c 2010-02-28 17:12:25.000000000 -0500 @@ -90,6 +90,10 @@ if (pcm->io.stream == SND_PCM_STREAM_CAPTURE) size -= pcm->offset;

+ /* Prevent accidental overrun of the fake ringbuffer */ + if (size >= pcm->buffer_attr.tlength) + size = pcm->buffer_attr.tlength-1; + if (size > pcm->last_size) { pcm->ptr += size - pcm->last_size; pcm->ptr %= pcm->buffer_attr.tlength; @@ -424,6 +428,7 @@ snd_pcm_pulse_t *pcm = io->private_data; const char *buf; snd_pcm_sframes_t ret = 0; + size_t writebytes;

assert(pcm);

@@ -445,13 +450,15 @@ (char *) areas->addr + (areas->first + areas->step * offset) / 8;

- ret = pa_stream_write(pcm->stream, buf, size * pcm->frame_size, NULL, 0, 0); + writebytes = size * pcm->frame_size; + ret = pa_stream_write(pcm->stream, buf, writebytes, NULL, 0, 0); if (ret < 0) { ret = -EIO; goto finish; }

/* Make sure the buffer pointer is in sync */ + pcm->last_size -= writebytes; ret = update_ptr(pcm); if (ret < 0) goto finish; @@ -528,6 +535,7 @@

dst_buf = (char *) dst_buf + frag_length; remain_size -= frag_length; + pcm->last_size -= frag_length; }

/* Make sure the buffer pointer is in sync */ @@ -730,6 +738,11 @@ pcm->offset = 0; /*pcm->underrun = 0;*/

+ /* Reset fake ringbuffer */ + pcm->last_size = 0; + pcm->ptr = 0; + update_ptr(pcm); + finish: pa_threaded_mainloop_unlock(pcm->p->mainloop);

--------------040006090607070407080605--