2009/2/14 Emanuel Rumpf <xbran(a)web.de>de>: Ah ... fine ! At LAU-ML, I found a message (02.02.2009) by Robin Gareus, which solves the problem: `echo -1 > /proc/sys/kernel/sched_rt_runtime_us` or edit /etc/sysctl.conf and add: kernel.sched_rt_runtime_us = -1 and his comment: """ indeed, jackd did not start unless run as root or until I changed /proc/sys/kernel/sched_rt_runtime_us It's the us (or .001% of CPU usage?!) above which FIFO and RR will be throttled to recover from a run-away rt process. - I'm not exactly sure why it affects jackd when run as "normal" user; maybe because with CPU load above the default 95% rt can not be guaranteed. There's a bit [off topic] but enlightening info at http://kerneltrap.org/mailarchive/linux-kernel/2008/8/16/2960524 """ Thanks -- Emanuel Rumpf