Jack RT stopped working after system update

Gerhard Lang lang.gerhard at gmail.com
Thu Jan 1 01:19:48 GMT 2009

Philip Schleihauf schrieb:
> Hello,
> Yesterday I hooked up my Ubuntu Studio box to the internet again for
> the first time in about a month and a half so I could get some files
> and programs, and also to update the system. There were a lot of
> updates, and the computer froze about 4/5 through installing the
> files, so I forced a restart.
> Restarted. Opening Synaptic gave me a message telling me to run "dpkg
> --configure -a". I did that and it seemed to finish installing the
> programs as it would normally.
> Now when I try to start Jack with RT enabled, it fails. It works
> without RT, and it worked before either way. I've messed around with
> the settings, but so far to no avail.
> Here is the output of the Messages window:
> 20:18:47.587 Patchbay deactivated.
> 20:18:47.680 Statistics reset.
> 20:18:47.718 ALSA connection graph change.
> 20:18:47.915 ALSA connection change.
> 20:19:24.476 Startup script...
> 20:19:24.479 artsshell -q terminate
> 20:19:24.926 Startup script terminated with exit status=256.
> 20:19:24.927 JACK is starting...
> 20:19:24.928 /usr/bin/jackd -R -dfreebob -r44100 -p1024 -n3 -D
> 20:19:24.943 JACK was started with PID=5732.
> jackd 0.109.2
> Copyright 2001-2005 Paul Davis and others.
> jackd comes with ABSOLUTELY NO WARRANTY
> This is free software, and you are welcome to redistribute it
> under certain conditions; see the file COPYING for details
> JACK compiled with System V SHM support.
> cannot use real-time scheduling (FIFO at priority 10) [for thread
> -1210870096, from thread -1210870096] (1: Operation not permitted)
> cannot create engine
> 20:19:24.958 JACK was stopped successfully.
> 20:19:24.959 Post-shutdown script...
> 20:19:24.961 killall jackd
> jackd: no process killed
> 20:19:25.374 Post-shutdown script terminated with exit status=256.
> 20:19:26.958 Could not connect to JACK server as client. - Overall
> operation failed. - Unable to connect to server. Please check the
> messages window for more info.
> I am using a Pentium 4 machine with 512MB ram, 58GB on this partition.
> I've got a FireWire card in a PCI slot to which a Presonus FireBox is
> attached. This is the first time I've had problems with the audio.
> I'm using the RT kernel
> I've got realtime checked in Jack settings, with 3 periods at 1024
> frames each. I've been using the freebob driver.
> All these settings are fine when realtime is not enabled. In a few
> days I am going to need to record about 8 tracks simultaneously (2
> fireboxes), and I can't see that happening without realtime
> scheduling.
> thanks,
> Phil
In start-up menue choose old rt-kernel (for me it's 2.6.24-23-rt)
Try ubuntustudio-controls (synaptic).
Make sure
/etc/security/limits.conf contents
@audio - rtprio 99
@audio - memlock unlimited (edit unlimited to 3/4 of your installed
memory and remove this explanation)
@audio - nice -19
make sure group "disk" exists for user and root
Good luck for your recording session and happy New Year

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