On 08/04/2011 07:35 AM, Kevin Ross wrote:
I've uploaded a patch to ticket 2727, at https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2727
The symptom: Using the Jack plugin causes whatever program is outputting audio to hang after about 10-20 seconds.
The cause: The plugin creates a pipe, so that the fd's could be polled to indicate completion of a transfer. However, the call to write() blocks when playing audio, as nothing actually reads from the pipe, and it fills up until it blocks.
The patch:
--- alsa-plugins-1.0.23/jack/pcm_jack.c 2010-04-16 04:11:10.000000000 -0700 +++ alsa-plugins-1.0.23.new/jack/pcm_jack.c 2011-08-03 21:54:51.795378947 -0700 @@ -307,6 +308,18 @@ return 0; }
+static int make_nonblock(int fd) {
int fl;if ((fl = fcntl(fd, F_GETFL)) < 0)return fl;if (fl & O_NONBLOCK)return 0;return fcntl(fd, F_SETFL, fl | O_NONBLOCK);+}
- static int snd_pcm_jack_open(snd_pcm_t **pcmp, const char *name, snd_config_t *playback_conf, snd_config_t *capture_conf,
@@ -363,6 +376,9 @@
socketpair(AF_LOCAL, SOCK_STREAM, 0, fd);
make_nonblock(fd[0]);make_nonblock(fd[1]);jack->fd = fd[0]; jack->io.version = SND_PCM_IOPLUG_VERSION;
Confirmed to be working. I'm going to send a git patch ASAP.
Cheers