[PlanetCCRMA] Weird problems using RT on FC6

[Stephan Neuhaus]

Hi,

I am experiencing weird problems when using realtime functionality on my 
FC6 system.  The machine is rock-stable when I refrain from doing any RT 
stuff, but when I enable RT, for example when starting jackd, then after 
some time, the machine will complain about missing interrupts, and 
especially about bad status on the ATA interface ("ATA: abnormal status 
0x7F on port 0xEC07", lost interrupt messages and so on).  Soon, there 
is no disk access anymore: if I can log in as root at all, shutdown just 
says "I/O error", which is very scary.  I have to power-cycle the 
machine in order to get it back up again.

This happens both with the CCRMA RT kernel 
(vmlinuz-2.6.21-0143.rt1.3.fc6) and with the stock FC6 kernel 
(vmlinuz-2.6.20-1.2948.fc6).  When I boot the RT kernel, sometimes this 
behavior happens right at boot time.

This is on a no-name PC with a Core2 Duo E6400 @ 2.13GHz and 1GB RAM.

What could it be?

I'm somewhat of a newbie reporting things like this, so if you need any 
more information, please tell me.

Fun,

Stephan