1.4.6: internal poll failure reading response from client B.Schaffl to a latency callback event about bschaffl HOT 9 CLOSED

I'm closing this issue here as it looks like a host-related problem and @drobilla already opened an issue there: drobilla/jalv#49.

from bschaffl.

I can't reproduce it on Ubuntu 20.04. It looks like your system doesn't like any live change in latency. But then, the host behaviour is odd.

I'm a bit surprised about calling jalv with sudo. And I also wonder where the error messages come from. Jalv or jackd? I've got jackd2 (1.9.12) running without any problems.

from bschaffl.

I'm a bit surprised about calling jalv with sudo

This was just to make sure permissions aren't a problem. It runs fine without sudo.

And I also wonder where the error messages come from. Jalv or jackd? I've got jackd2 (1.9.12) running without any problems.

jackd2 doesn't yet run on FreeBSD. People are working on making it compatible.

from bschaffl.

It runs fine without sudo.

Do you mean "it runs in the same way" (I guess you mean this) or do you mean "it runs without any errors" ? And do you see the same problem with other hosts (like Carla, Ardour, ...)?

I think it has something to do with jalv and the jack/jack2 problem. And it is somehow related to sjaehn/BChoppr#12. The error messages look like jack.

The only maybe "evil" thing that B.Schaffl does is dynamicly changing the latency value by re-calculating

It's the hosts task to handle the latency value reported by the plugin. Maybe @drobilla (who made jalv and the most of the LV2 tools) knows a bit more.

from bschaffl.

No idea, sorry, I'd have to look in to it. Jalv does attempt to report changed latency to JACK. I have no idea off the top of my head whether how/when/etc it does so is correct, though. Maybe @x42 who originally wrote that code and generally understands JACK latency far better will have some idea.

from bschaffl.

Last I check (3-4 years ago) jalv did not notify jack when the plugin's latency changes.
However. changing jack port connections triggers a latency-callback, and jalv will use the current value.
check with jack_lsp -l

from bschaffl.

drobilla/jalv@cebeaf2

from bschaffl.

@drobilla so the patch calls jack_recompute_total_latencies() whenever the plugin's latency changes from the process-callback. -- No idea if that works with jack1, ask some JACK threading expert.

The rest of the code reads fine.

from bschaffl.

jack_recompute_total_latencies() is a server call. It is not legal to make server calls from within a server callback (like the process callback).

from bschaffl.