[PlanetCCRMA] Weird problems using RT on FC6

[Fernando Lopez-Lezcano]

On Fri, 2007-05-25 at 16:28 +0200, Stephan Neuhaus wrote:
> 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.

Hmmm, sounds bad indeed and is probably a bug in the stock kernel with
your particular hardware configuration (as it happens in both the Fedora
kernel and the Planet CCRMA kernel with the rt patch). What is the
output of /sbin/lspci?

Sounds like an IRQ routing problem. But there's also the bad status
messages as well. 

Does the machine run fine with any other operating system? This could be
something as simple as a bad ATA cable...

-- Fernando