Re: [LAU] [Jackit-devel] [PATCH] JACK 0.109.2 alsa device disconnect patch

Hi all, I just fitted Sean Meiners' alsa device disconnect patch for JACK 0.109.2. It enables jackd to detach from the ALSA device, letting its use by other non-JACK programs whilst in the middle of a jack session, without closing jackd and its clients. IMHO very useful for i.e common builtin laptop soundcards which don't support more than one alsa-direct audio app at once (also commonly known as "no hardware mixing soundcards"). You get an additional example client: jack_device_connect (based on jack_freewheel, its arguments are "y" or "n") which you use to make jack release and re-hook to the audio card. Time is paused and all audio from jack is of course muted and jackd and its client applications are put into this fake-freewheel mode while jack has released the device; they continue producing and consuming audio upon jackd re-attaching to the audio device, with the command "jack_device_connect y". The original version was for jack 0.100.0, I just modified it to make it patch successfully on jack 0.109.2. I don't have so advanced programming skills to understand its inner working, but from a quick read of the code, for what I can understand, I saw it mainly adds some functions in jackd (jack_device_disconnect() and jack_device_connect()in jackd/engine.c) and libjack (jack_set_connected() in client.c, jack_driver_nt_disconnect() and jack_driver_nt_connect() in driver.c) to dis/connect to the alsa device. I was asked on this list about the interaction of this patch with realtime watchdogs. I didn't encounter any problem, they were never triggered (and no crashes or weird things ;) ) as in normal operation, because they enter this freewheeling-like mode. I contacted Sean and asked him if it was this way, and he replied: like >freewheel mode (so that jack clients don't freeze up). And then shuts >down the alsa driver. As for the watchdog, I don't remember anything >about that, but if I had to guess I'd say it's because jack is put into >a fake-freewheel mode. Hope it is useful to who wants to try it: just use jack_device_connect n and voila, you can watch youtube videos or use that strange non- jack aware application you need in that moment, _without_ closing any jack program. When you're done, just use ja