Ubuntu – Unable to start jack (Cannot allocate memory)

jack

I want to use PulseAudio on top of jack, so I've turned pulse off and now want to start jack using qjackctl. However, this results in the following error log:

22:14:15.933 Patch Panel disabled
22:14:15.940 Reset statistics.
22:14:15.953 Changed ASLA connection.
22:14:15.970 D-BUS: Service available (org.jackaudio.service aka jackdbus).
Cannot connect to server socket err = File or directory not found
Cannot connect to server socket
jack server is not running or cannot be started
22:14:15.980 Updated visualization of ASLA connections
22:14:18.147 D-BUS: Unable to start JACK server
Cannot connect to server socket err = File or directory not found
Cannot connect to server socket
jack server is not running or cannot be started
Fri Jul 20 22:14:18 2012: Starting jack server...
Fri Jul 20 22:14:18 2012: JACK server starting in realtime mode with priority 10
Fri Jul 20 22:14:18 2012: [1m[31mERROR: Cannot lock down 82246176 byte memory area (Cannot allocate memory)[0m
Fri Jul 20 22:14:18 2012: control device hw:0
Fri Jul 20 22:14:18 2012: control device hw:0
Fri Jul 20 22:14:18 2012: [1m[31mERROR: Failed to acquire device name : Audio0 error : Cannot allocate memory[0m
Fri Jul 20 22:14:18 2012: [1m[31mERROR: Audio device hw:0 cannot be acquired...[0m
Fri Jul 20 22:14:18 2012: [1m[31mERROR: Cannot initialize driver[0m
Fri Jul 20 22:14:18 2012: [1m[31mERROR: JackServer::Open() failed with -1[0m
Fri Jul 20 22:14:18 2012: [1m[31mERROR: Failed to open server[0m
Fri Jul 20 22:14:19 2012: Saving settings to "/home/jan/.config/jack/conf.xml" ...
22:14:24.418 Cannot connect to JACK server as client - connection failed. See message dialog for details.
Cannot connect to server socket err = File or directory not found
Cannot connect to server socket
jack server is not running or cannot be started

(Several messages were in German, I did my best translating them)

The pulseaudio process is defenitely not running.

I use Ubuntu 12.04 64 bit with an NVIDIA audio card.

Best Answer

Ok, got it: I had to add myself to the group audio:

usermod -a -G audio theusername

Group membership is only updated on login, so you need to log out and in again (or just reboot).