Jack fails to start in real-time mode

[ClaudioRJ]

Binary package hint: qjackctl

I use to study music, when Windows was my OS, with Encore application. When I finally moved to Ubuntu I never have to study music anymore. Since now. I looked for some Linux application that could read a .mid file and not only beeing able to play it, but to separate voices so I could mute some in other to study others.

I've found Rosegarden, a great application, and I noticed that it fits to my necessities.

But, when I run Rosegarden I get this message:
"Failed to connect to JACK audio server.

Rosegarden could not connect to the JACK audio server. This probably means JACK server is not running.

If you want to be able to play or record audio files or use plugins, you should exit Rosegarden and start the JACK server before running Rosegarden again."

And as Rosegarden comes up to memory, a Jack Audio Connection Kit (qjackctl application) also is initialized. And I think that this app is intended to start the audio server. But, after trying to do so, it shows an error message box (title: Error - JACK Audio Connection Kit):
" Could not connect to JACK server as client.
- Overall operation failed.
- Unable to connect to server.
Please check the messages window for more info."

The messages windows says:
"13:33:47.858 Patchbay deactivated.
13:33:48.729 Statistics reset.
13:33:48.866 Startup script...
13:33:48.868 artsshell -q terminate
13:33:48.872 ALSA connection graph change.
sh: artsshell: not found
13:33:49.527 Startup script terminated with exit status=32512.
13:33:49.528 JACK is starting...
13:33:49.528 /usr/bin/jackd -R -dalsa -dhw:0 -r44100 -p1024 -n2
13:33:49.568 JACK was started with PID=15544.
no message buffer overruns
jackd 0.116.1
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 -1212qjackctl430656, from thread -1212430656] (1: Operation not permitted)
cannot create engine
13:33:49.581 JACK was stopped successfully.
13:33:49.581 Post-shutdown script...
13:33:49.582 killall jackd
13:33:49.766 ALSA connection change.
jackd: nenhum processo morreu
13:33:50.017 Post-shutdown script terminated with exit status=256.
13:33:51.800 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info."

As I'm not an expert in Linux, and I'm an Ubuntu fan, I really would like to know how can I smoothly play my midi files among Rosegarden app without doing anything more technically unknown to me.

My environment:
Architecture: i386
DistroRelease: Ubuntu 9.04
ExecutablePath: /usr/bin/qjackctl
Uname: Linux 2.6.28-13-generic

[Neal Crook (neal-pippaluk)]

I have the same problem, using jackd and qjackctl on Kubuntu 9.04, and repeatable when starting qjackctl from the command line (recipe below). jackd and qjackctl (and a bunch of other stuff) were installed for me as dependencies when I installed rosegarden.

"sudo apt-cache show jackd" reports:

Version: 0.116.1-3ubuntu3

"sudo apt-cache show qjackctl" reports:

Version: 0.3.4-0ubuntu2

"uname -a" reports:

Linux orac 2.6.28-9-generic #29-Ubuntu SMP Sun Mar 8 02:03:17 UTC 2009 i686 GNU/Linux

Recipe to reproduce the bug:

> qjackctl

/usr/bin/qjackctl: 28: list: not found [ seems to be complaining about the line: "JACK=$($PACTL list | grep jack-sink)" ]
Using JACK for audio

[gui entitled "JACK Audio Connection Kit [(default)] Stopped." appears. Press "start" button and a console window appears containing the following text]

22:37:04.981 Patchbay deactivated.
22:37:05.251 Statistics reset.
22:37:05.320 ALSA connection graph change.
22:37:05.808 ALSA connection change.
22:40:18.412 Startup script...
22:40:18.413 artsshell -q terminate
sh: artsshell: not found
22:40:18.836 Startup script terminated with exit status=32512.
22:40:18.838 JACK is starting...
22:40:18.839 /usr/bin/jackd -R -dalsa -dhw:0 -r44100 -p1024 -n2
22:40:18.896 JACK was started with PID=12909.
no message buffer overruns
jackd 0.116.1
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 -1211020544, from thread -1211020544] (1: Operation not permitted)
cannot create engine
22:40:19.004 JACK was stopped successfully.
22:40:19.005 Post-shutdown script...
22:40:19.006 killall jackd
jackd: no process killed
22:40:19.453 Post-shutdown script terminated with exit status=256.
22:40:21.012 Could not connect to JACK server as client. - Overall operation failed. - Unable to connect to server. Please check the messages window for more info.

regards,

Neal.

[Neal Crook (neal-pippaluk)]

D'oh!

after more googling, seems like "artsshell" error was a false trail:

http://ubuntuforums.org/archive/index.php/t-1149712.html

fix is as simple as being root to start jack:

> sudo qjackctl &

[ press "start" ]

> rosegarden

Neal.

[raboof (arnouten)]

Running qjackctl is absolutely not a suitable solution to this problem.

The root of your problem is this:

cannot use real-time scheduling (FIFO at priority 10) [for thread -1211020544, from thread -1211020544] (1: Operation not permitted)

JACK is configured to use 'Realtime' mode, but your system is not configured to allow you to use Realtime mode. http://trac.jackaudio.org/wiki/Troubleshooting explains how to troubleshoot this problem - though I believe starting from Karmic this is fixed in the default configuration (not sure).

[William L. Blackburn III (blackburnw)]

to run jack in real time mode I am pretty sure that you need a real time kernel. If you haven't already, check this page out and download the low latency or real time kernel free of charge.

https://help.ubuntu.com/community/UbuntuStudioPreparation

hope this helps

also, try changing the frames/buffer and other settings that affect the latency time that is computed.

[William L. Blackburn III (blackburnw)]

sorry about the double post.
here is my kernel

Linux tertl3-desktop 2.6.32-22-lowlatency #33-Ubuntu SMP PREEMPT Tue May 11 16:00:02 UTC 2010 x86_64 GNU/Linux

P.S. Jack can be hairy, but it does work. Check to make sure your sound card isn't the problem too.

[Alessio Treglia (quadrispro)]

Installing a real-time kernel would be the solution.
So, closing for now.