Dne 20.3.2017 v 08:39 Jaroslav Kysela napsal(a): > Dne 16.3.2017 v 13:23 Max Kellermann napsal(a): >> Hi, >> >> I have received a bug report for the Music Player Daemon which >> complains about a freezing MPD process, after I switched MPD's ALSA >> output to non-blocking mode: >> >> https://bugs.musicpd.org/view.php?id=4662 >> >> This happens when snd_pcm_drain() is used on a dmix PCM which is in >> SND_PCM_NONBLOCK mode. snd_pcm_drain() will be called repeatedly, >> because ALSA's file descriptor is always ready. >> >> According to my research, the bug is in __snd_pcm_dmix_drain(). This >> function always returns -EAGAIN when SND_PCM_NONBLOCK is set: >> >> if (pcm->mode & SND_PCM_NONBLOCK) >> return -EAGAIN; >> >> This comes very early in the function, before any other relevant >> checks. It can never finish that way, and calling it again at any >> time will never do anything. Thus, snd_pcm_drain() appears to be >> broken in non-blocking mode. > > Could you test > http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=fdc898d41135b26772d0fffe07e9eb0de6597125 > ? There should be a loop with -EAGAIN, but this loop should end when > then samples and drained. Oops. I used wrong handle to check the state. Use commit http://git.alsa-project.org/?p=alsa-lib.git;a=commitdiff;h=e4377b16454f3b7b222613a571bf4244ebd28e56 , too. http://git.alsa-project.org/?p=alsa-lib.git;a=summary Jaroslav -- Jaroslav Kysela <perex@xxxxxxxx> Linux Sound Maintainer; ALSA Project; Red Hat, Inc. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
