[linux-audio-user] problem: jackd, real-time, permissions, RLIMITS

I've been working on this problem now for days, and I can't see where
my mistake is (if I have made one). I have two identical computers
running Gentoo with the proaudio overlay. I have 2.6.16-rt29 working
on one computer, using RLIMITS. I can start jackd through qjackctl
with the realtime option, 64 frames/period, 2 periods/buffer. I get no
error messages and only get an occasional xrun when starting new
applications. I have tried to duplicate that setup on another
computer; however, I always get these errors, which don't occur on the
properly-functioning computer:

cannot lock down memory for jackd (Cannot allocate memory)
cannot use real-time scheduling (FIFO at priority 20) [for thread
49156, from thread 49156] (1: Operation not permitted)
cannot use real-time scheduling (FIFO at priority 10) [for thread
65541, from thread 65541] (1: Operation not permitted)

This is followed by tons of xruns.

Here is more relevant information on my configuration (identical on
both computers):

renick@email-addr-hidden ~ $ uname -a
Linux localhost 2.6.16-rt29 #1 PREEMPT Sat Jul 22 21:16:25 JST 2006
i686 Intel(R) Pentium(R) M processor 1.70GHz GenuineIntel GNU/Linux
renick@email-addr-hidden ~ $ groups
wheel floppy audio cdrom video usb users

# /etc/security/limits.conf
# REALTIME support for audio group users
@audio - rtprio 90
@audio - nice -5
@audio - memlock 512000

localhost renick # equery which pam
/usr/portage/local/layman/pro-audio/sys-libs/pam/pam-0.78-r6.ebuild

localhost renick # emerge -s pam
* sys-libs/pam
      Latest version available: 0.78-r6
      Latest version installed: 0.78-r6

localhost renick # equery which jack-audio-connection-kit
/usr/portage/local/layman/pro-audio/media-sound/jack-audio-connection-kit/jack-audio-connection-kit-0.9999.ebuild

localhost renick # emerge -s jack-audio
* media-sound/jack-audio-connection-kit
      Latest version available: 0.9999
      Latest version installed: 0.100.7-r3

This version, 0.100.7-r3, is the same version that is working on my
other computer.

I've asked on the proaudio list about this problem, but I haven't
received an answer so I am asking here (is a four-day lag
cross-posting? if so, sorry...). What could be causing the jack
errors? Are there any other places besides /etc/security/limits.conf
that I should be checking for correct configuration? Advice?

Thanks!

Renick
Received on Fri Jul 28 04:15:04 2006