qjackconnect.
I'm currently trying to see if I can start the stuff from
the text console so that I can try to catch some register dumps through
the sysrq magic key...
I don't have the time now to analyze the results but it would seem the
problem is freqtweak in combination with jackd. When the system freezes
after starting stuff from a text console, <alt>sysrq-p prints
information about the current registers and the printout of repeated
dumps only shows the jackd and freqtweak processes over and over again.
Somehow they must be deadlocking.
Good news (apparently - most probably the machine I'm testing on will
freeze while I'm typing this message :-)
The problem with 2.4.20 appears to have been ext3. I finally got a trace
of the deadlocked processes through the sysrq key (after retyping lots
of boring numbers from the screen) and ksymoops is pointing to something
stuck in ext3. With that clue I went to the ext3 site:
http://www.zip.com.au/~akpm/linux/ext3/
And sure enough there were patches for 2.4.20 and one of them was a
deadlock condition. I applied them, rebuilt the kernel and the machine
appears to be _finally_ happy (I'm still typing and it has not
deadlocked).
This is with 2.4.20 + lowlat + preempt + o(1) scheduler (most of Con
Koliva's patchset) plus some extras, running latest alsa cvs plus jack
and a bunch of jack clients.
Well, it did not freeze after all... let's see if I can get to the send
message button before it does :-)
-- Fernando