Re: Maybe a bug

From: Maciej W. Rozycki (
Date: Wed Feb 21 2001 - 11:16:56 EST

On Mon, 19 Feb 2001, Matthias Kleine wrote:

> The problem appears on a machine using the pretty new ASUS CUVX-D Dual Socket
> 370 Motherboard, so there may be a chance for an unknown bug ;-). With NMI
> watchdog activated, a 2.4.x Kernel is not willing to boot on this machine, it
> just stops booting at a very early time, giving the latest message
> "activating NMI watchdog ..." and then blocking completely. Therefore, I set

 Hmm, you state the watchdog works from time to time and the log you
provided confirms the statement -- it reports:

> ..TIMER: vector=49 pin1=2 pin2=0
> activating NMI Watchdog ... done.

What chipset do you use (check with lspci)?

 In any case the code should not hang there in any case -- it the watchdog
appears stuck, it reports it and goes on. A hang almost surely means
hardware locked up.

> nmi_watchdog = 0, when the system boots properly, but leaves some crucial
> message in /var/log/messages:
> Feb 19 19:37:17 delphin kernel: testing the IO APIC.......................
> Feb 19 19:37:17 delphin kernel:
> Feb 19 19:37:17 delphin kernel: WARNING: unexpected IO-APIC, please mail
> Feb 19 19:37:17 delphin kernel: to
> Feb 19 19:37:17 delphin kernel: .................................... done.

 No need to worry. The code finds an unknown bit set in the version
register (well, the bit is unknown to the code -- the bit is documented
and we should mark it as such in the code soon, probably as a part of P4

> Let me say, that the system seems to be usable after the boot, but when
> starting X, some strange drawings hush over the screen. Afterwards, X is
> running properly. Using a 2.2.x kernel this behaviour doesn't appear, with a
> 2.4.x kernel, it is reproducable.

 Various reports seem to indicate XFree86 cannot cope with 2.4 SMP as it
should. It's possible they do not handle synchronization well.

+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+        e-mail:, PGP key available        +

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