[LAU] Realtime, but many xruns when jack is started. Debian Etch

On Debian Etch, using kernel 2.6.18-5-686, which I presume is a realtime one, as when I start jack with qjackctl, and with the realtime box checked, jack doesn't complain. Looking at messages though, shows lots of xruns, although no music apps are being used. I had this problem on Fedora 7. I'd installed the low latency kernel, and associated packages from planetccrma, and again jacks messages were showing lots of xruns. There was an updated pam that came with the kernel download, which left an /etc/security/limits.conf.rpmnew, and Fernando suggested adding the changes to the existing file, as the default setup for jack-audio-connection-kit in the limits.conf file set rtprio at 20. That resolved the problem on Fedora 7. No more messages about xruns. I tried the same few lines, as below, in the limits.conf file in Etch, but to no success, and there are no default priorities for jack there anyway. # limit realtime and memory locking access to users in the group audio # there is no way to say "allow locking all memory", 4G should be enough # #* - rtprio 0 #* - nice 0 # #@audio - rtprio 99 #@audio - nice -10 #@audio - memlock 4000000 # or (default) allow everyone access * - rtprio 99 * - nice -10 * - memlock 4000000 I don't have the realtime-lsm package installed on Etch yet, as I wanted to get opinions from the list first. Thanks for any help/suggestions. Nigel. jackd is version 0.101.1-2 on Etch qjackctl is version 0.2.21-1