Max Kellermann <[EMAIL PROTECTED]> wrote: > On 2008/10/01 12:36, Eric Wong <[EMAIL PROTECTED]> wrote:
<snip> I'll try to look more closely at the other stuff when I'm more awake. > > Adding a user-configurable async flag to each audio_output > > (defaulting to off for backwards compatibility) for playback could > > be useful. This way users can choose which outputs they value over > > others. > > There could be a "primary" output - the first one which is configured? No "magic" stuff like this in the config file, please. > > enable/disable/close/open should always be async, though; just > > playback should be (optionally) synchronous. > > Why? open() is my favorite method which might block the full MPD > daemon if that isn't performed asynchronously. I meant they should be asynchronous from the perspective of other mpd threads. Each audio_output thread can block all they want as long as the rest of mpd doesn't block on them. > > synchronous notification is much easier in some cases. It is much > > nicer for some "fast" things such as dropping the output buffer when > > skipping tracks; but I agree that async is much better in many > > cases, too... > > But with my code, all N output devices can drop their output buffer at > the same time. That may require some long lasting blocking system > calls. I meant the userspace output buffer we use for xfade/volume effects (and only as an example). We should not rely on the external dependencies to do async stuff right since there are too many variables to account for. > > I would just use pthread_mutex_trylock() and then broadcast if I get > > locks from the required set of outputs... > > Too complicated, for no good reason. Dunno, haven't tried it yet :) > > No races, but one bug and the aforementioned issue: > > > > A definite bug: pthread_cond_wait is subject to spurious wakeups so you > > need to restart pthread_cond_wait if pending is not set. > > assert(notify->pending) is wrong after pthread_cond_wait. > > It is? That's not documented... well, to be on the safe side, I have > added a patch for that. It's in the POSIX manpages. The section 3 manpages I got from Debian seem mainly for LinuxThreads. -- Eric Wong ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Musicpd-dev-team mailing list Musicpd-dev-team@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/musicpd-dev-team
