This patch fixes polling in alsa-to-jack plugin. It makes poll()+_poll_revents() return correct values when there's something to read/write. It also makes jack pcm survive snd_pcm_recover(-EPIPE). --- jack/pcm_jack.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 55 insertions(+), 7 deletions(-)

diff --git a/jack/pcm_jack.c b/jack/pcm_jack.c index 7a8b24d..36fbdc9 100644 --- a/jack/pcm_jack.c +++ b/jack/pcm_jack.c @@ -42,6 +42,7 @@ typedef struct { unsigned int num_ports; unsigned int hw_ptr; unsigned int sample_bits; + snd_pcm_uframes_t min_avail;

unsigned int channels; snd_pcm_channel_area_t *areas; @@ -50,6 +51,41 @@ typedef struct { jack_client_t *client; } snd_pcm_jack_t;

+static int snd_pcm_jack_stop(snd_pcm_ioplug_t *io); + +static int pcm_poll_block_check(snd_pcm_ioplug_t *io) +{ + static char buf[32]; + snd_pcm_sframes_t avail; + snd_pcm_jack_t *jack = io->private_data; + + if (io->state == SND_PCM_STATE_RUNNING || + (io->state == SND_PCM_STATE_PREPARED && io->stream == SND_PCM_STREAM_CAPTURE)) { + avail = snd_pcm_avail_update(io->pcm); + if (avail >= 0 && avail < jack->min_avail) { + while (read(io->poll_fd, &buf, sizeof(buf)) == sizeof(buf)); + return 1; + } + } + + return 0; +} + +static int pcm_poll_unblock_check(snd_pcm_ioplug_t *io) +{ + static char buf[1]; + snd_pcm_sframes_t avail; + snd_pcm_jack_t *jack = io->private_data; + + avail = snd_pcm_avail_update(io->pcm); + if (avail < 0 || avail >= jack->min_avail) { + write(jack->fd, &buf, 1); + return 1; + } + + return 0; +} + static void snd_pcm_jack_free(snd_pcm_jack_t *jack) { if (jack) { @@ -81,14 +117,10 @@ static int snd_pcm_jack_poll_revents(snd_pcm_ioplug_t *io, struct pollfd *pfds, unsigned int nfds, unsigned short *revents) { - static char buf[1]; - assert(pfds && nfds == 1 && revents);

- read(pfds[0].fd, buf, 1); - *revents = pfds[0].revents & ~(POLLIN | POLLOUT); - if (pfds[0].revents & POLLIN) + if (pfds[0].revents & POLLIN && !pcm_poll_block_check(io)) *revents |= (io->stream == SND_PCM_STREAM_PLAYBACK) ? POLLOUT : POLLIN; return 0; } @@ -105,7 +137,6 @@ snd_pcm_jack_process_cb(jack_nframes_t nframes, snd_pcm_ioplug_t *io) snd_pcm_jack_t *jack = io->private_data; const snd_pcm_channel_area_t *areas; snd_pcm_uframes_t xfer = 0; - static char buf[1]; unsigned int channel; for (channel = 0; channel < io->channels; channel++) { @@ -145,7 +176,7 @@ snd_pcm_jack_process_cb(jack_nframes_t nframes, snd_pcm_ioplug_t *io) xfer += frames; }

- write(jack->fd, buf, 1); /* for polling */ + pcm_poll_unblock_check(io); /* unblock socket for polling if needed */

return 0; } @@ -154,9 +185,26 @@ static int snd_pcm_jack_prepare(snd_pcm_ioplug_t *io) { snd_pcm_jack_t *jack = io->private_data; unsigned int i; + snd_pcm_sw_params_t *swparams; + int err;

jack->hw_ptr = 0;

+ jack->min_avail = io->period_size; + snd_pcm_sw_params_alloca(&swparams); + err = snd_pcm_sw_params_current(io->pcm, swparams); + if (err == 0) { + snd_pcm_sw_params_get_avail_min(swparams, &jack->min_avail); + } + + /* deactivate jack connections if this is XRUN recovery */ + snd_pcm_jack_stop(io); + + if (io->stream == SND_PCM_STREAM_PLAYBACK) + pcm_poll_unblock_check(io); /* playback pcm initially accepts writes */ + else + pcm_poll_block_check(io); /* block capture pcm if that's XRUN recovery */ + if (jack->ports) return 0;