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Re: FC4 & FC5 Kernel IRQ Problems IBM Thinkpad R30

James Sanders wrote:
> Hi,
> I have an IBM Thinkpad R30 Laptop and anytime I upgrade my kernel i
> have to add the command /irqpoll/ to the end of the line in grub.
> This didn't happen when FC4 first came out, it was fine. Then a change was 
> probably made in a new kernel maybe a couple months after FC4 release,
> and this started happening
> Something to do with IRQ #15 Nobody Cared
> booting with /irqpoll/ works fine, but why is this? This still happens on the 
> FC5 test releases.

This is almost certainly a hardware bug, a kernel driver bug, or
slightly broken hardware. I'm leaning towards the latter possibility --
I know a number of Red Hat folks have T30s, so I'd expect them to have
encountered any problems.

First question -- are you running Nvidia, ATi, VMware, or other
proprietary drivers? (You should know if you are -- you'd have had to
install them). If so, see if you can replicate without them.

Second question: look in /proc/interrupts and see what's on IRQ 15. (The
first number in each line is the IRQ number). I'd guess it's ide1, the
IDE controller which is probably hooked up to your CD drive.

What's happening is that the kernel is receiving interrupts on interrupt
15, and doesn't know what to do with them.

You probably ought to 'bugzilla' [1] this (a quick check can't see any
duplicates). In the meantime, there are a few things to try out.

You might want to check to see you've got the latest BIOS for the
(Usual disclaimer applies -- updating BIOSes can occasionally go wrong).

I don't know if you've got hyperthreading turned on -- if you have, try
turning it off. If it's off, try turning it on and installing a SMP

If that works, try booting a FC5 kernel with the lapic option. If *that*
works, it's your Programmable Interrupt Controller that's causing the

There's a slight chance that adding "hdc=nodma" will also change the
symptoms, too.

One more hint: when you want to start a new conversation on the list,
write a new e-mail. Don't reply to an existing one: this puts threading
information into your e-mail headers. That means it appears as part of
another "thread" in threaded mail clients, which means many people
(especially those more likely to respond) will just assume it's a reply
to a thread they might not be interested in.

Hope this helps,

[1] Enter it into https://bugzilla.redhat.com/bugzilla/index.cgi
E-mail address: james | Ankh-Morpork people considered that spelling was a
@westexe.demon.co.uk  | sort of optional extra. They believed in it in the
                      | same way they believed in punctuation; it didn't
                      | matter where you put it, so long as it was there.
                      |     -- "The Truth", Terry Pratchett

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