[PlanetCCRMA] Fwd: jack2

Niels Mayer nielsmayer at gmail.com
Mon Apr 19 12:46:48 PDT 2010

I figured out what happened with qjackctl&&jack when
/etc/security/limits.conf got set like this:

## Automatically appended by jack-audio-connection-kit

@jackuser - rtprio 20

@jackuser - memlock 4194304

## Automatically appended by jack-audio-connection-kit

@pulse-rt - rtprio 20

@pulse-rt - nice -20

## Automatically appended by the Planet CCRMA jack-audio-connection-kit

* - rtprio 99

* - memlock 4194304

* - nice -10

What happened: I didn't notice /etc/security/limits.conf.rpmnew had been
installed, perhaps in deinstalling F12's jack-audio-connection-kit, or from
upgrading to CCRMA's. The rpmnew removed the "Automatically appended by
jack-audio-connection-kit" sections; had CCRMA's jack been installed "on
top" of the RPMNEW, the spurious "rtprio 20" and "nice -20" would never had
been there, only the the 'Automatically appended by the Planet CCRMA
jack-audio-connection-kit' section.

The upshot is that this strange combination of settings would cause jack to
emit errors like:

Cannot use real-time scheduling (RR/60)(1: Operation not permitted)

AcquireSelfRealTime error

And may also be to blame for the lockup problem I experienced on this
machine, IMHO in conjuction w/ pulseaudio libs locking up, perhaps because
they were running at "rtprio 20" and "nice -20" vs jack's 60: thus my
earlier hypothesis....


Rebooting with a "fixed" /etc/security/limits.conf  (with
/etc/groups:jackuser set to include the user running jack) containing:

@jackuser - rtprio 99

@jackuser - memlock 4194304

@jackuser - nice -10

Makes jack work correctly, and without error output "Cannot use real-time
scheduling (RR/60)" in log output (despite the "RT" indicator flashing in

With the above limits.conf, my jack log ends up looking like this:

11:38:13.962 JACK is starting...

11:38:13.962 /usr/bin/jackd -dalsa -dhw:M66 -r44100 -p256 -n2 -Xseq -zs -H
> -M

11:38:13.976 JACK was started with PID=3415.

11:38:14.346 ALSA connection change.

11:38:14.347 ALSA connection graph change.

no message buffer overruns

no message buffer overruns

jackdmp 1.9.4

Copyright 2001-2005 Paul Davis and others.

Copyright 2004-2009 Grame.

jackdmp 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 server starting in realtime mode with priority 60


Acquire audio card Audio1

creating alsa driver ... hw:M66|hw:M66|256|2|44100|0|0|hwmon|hwmeter|-|32bit

Using ALSA driver ICE1712 running on card 1 - M Audio Delta 66 at 0xec00,
> irq 19

configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods

ALSA: final selected sample format for capture: 32bit integer little-endian

ALSA: use 2 periods for capture

ALSA: final selected sample format for playback: 32bit integer little-endian

ALSA: use 2 periods for playback

11:38:15.236 ALSA connection graph change.

port created: Midi-Through:midi/playback_1

port created: Midi-Through:midi/capture_1

port created: MT4:midi/playback_1

port created: MT4:midi/capture_1

port created: MT4:midi/playback_2

port created: MT4:midi/capture_2

port created: MT4:midi/playback_3

port created: MT4:midi/capture_3

port created: MT4:midi/capture_4

port created: MT4:midi/capture_5

port created: DJ-Console-(WE):midi/playback_1

port created: DJ-Console-(WE):midi/capture_1


-- Niels
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