I'm seeing no realtime threads from pipewire jack in Trixie. Pipewire seems to be following rlimits for nice but not passing on realtime priority. It appears to itself be gaining realtime priority for it's data loop thread.
I can get realtime threads through yabridge and alsa but not pipewire jack. Logging is not helping with the source of the problem. It was entirely functional in bookworm. I've tested with rtkit enabled and disabled. With rtkit enabled, pipewire doesn't seem to request realtime access but other apps do successfully. With rtkit disabled pipewire also doesn't pass realtime priority to jack threads but I don't find logging complaining that it tried and failed. I have other applications (yabridge, bitwig/reaper through alsa) that gain realtime access without issue but I'm also seeing ardour complain that it can't get realtime IO threads and from the ardour code in git that's entirely rlimit based. If this is a bigger problem than pipewire there's some evidence for it but a lot of evidence against. I haven't found any bug reports in the pipewire bug tracker that seem related and post 1.4.2 release. I'm using the xanmod 6.15.9-x64v3 kernel but also tested with 6.12 from trixie. Neither have CONFIG_RT_GROUP_SCHED enabled so it doesn't seem to be a cgroup interaction. Both have CONFIG_PREEMPT_DYNAMIC. I don't have jackd or jackd2 installed though I did with bookworm and tested with and without (after purge) and the ld.so.conf.d file is in place as per the package. Even so I tested via pw-jack and no difference.
