[1.0.95] LMMS doesn't reconnect to JACK ports after kicked from JACK (Opening/Closing Zyn GUI)

[unfa]

After recent update form KX Studio, I've noticed that LMMS doesn't handle something it handled in the past - JACK timeout kicks.

When I open up ZynAddSubFX GUI, lots of stuff happens - LMMS disconnects from JACK, recording screencasting applications loose A/V sync or crash.

LMMS always have been reconnecting to JACK (system:playback_1, system:playback_2).

Now it's worse than before - I never had LMMS crash Marteen Baert's Simple Screen Recorder (https://github.com/MaartenBaert/ssr). It was the ONLY screencasting tool that didn't loose A/V sync or crash when I opened/closed Zyn GUI in LMMS while recording a video. Now SSR can't handle it too (the audio thread crashes, then the whole program crashes) I wonder if LMMS changed so much in this regard or SSR has a new problem too.

To reproduce:

1. Run LMMS with JACK interface;
2. Open/Close Zyn several times while playing music;
3. Wait until you hear silence;
4. Reconnect LMMS manually to JACK system output;
5. Repeat from 2.

BTW: Is there a way to make Zyn GUI opening/closing not such an earthquake to the whole system? It'd be much easier to record LMMS screencasts (I'd release much more videos if this wasn't a problem - it's a showstopper).

PS: Maybe increasing JACK client timeout would fix this issue for me? It was 500 ms I kicked it up to 2000 ms.

[unfa]

Here's a related issue in the SSR project:
MaartenBaert/ssr#250

[softrabbit]

LMMS always have been reconnecting to JACK (system:playback_1, system:playback_2).

Any idea in which version this has changed? Looking at the code it seems to me like manual reconnection has been the intended behavior since at least 2009.
https://github.com/LMMS/lmms/blame/master/src/core/audio/AudioJack.cpp#L110

[tresf]

Consolidated to #1467, "Better JACK support" issue.

[serdnab]

I'm interested in fixing this, so @tresf, what's the desired behavior, manual reconnection or automatic?

[tresf]

@serdnab I honestly don't know what's best behavior. I'm not a JACK user, perhaps @Umcaruje, @unfa or someone more familiar with Jack should weigh in on this?

I've read the bug description several times. What I'm reading is that when opening/closing the Zyn UI by causing an abrupt disconnect with the JACK server:

I wonder if LMMS changed so much in this regard or SSR has a new problem too.

Probably. Here's the list of commits leading up to the stable-1.1 release:.
If a code change introduced this behavior, it's likely to be somewhere in side here: https://github.com/LMMS/lmms/commits/stable-1.1/plugins/zynaddsubfx

[serdnab]

I was doing more testing and I realized that it is better to leave the behavior as it is (manual) because changing it to automatic can complicate troubleshooting a bad connection with jack (in other cases apart from the problem with zyn gui).