Re: Failing back to INSANE timesource :) Time stopped today.

From: Maciej W. Rozycki
Date: Tue Apr 20 2004 - 07:43:45 EST

On Tue, 20 Apr 2004, Niclas Gustafsson wrote:

> I've now been running the system since last week, about 6 days now with
> sometimes quite high load, both in regard to CPU usage and network
> traffic.
> And it seems to be running just fine with the patch from Maciej.

I'm glad to read this.

> I've got a couple of questions,
> When was this bug introduced? Was it 2.6.1 ( or rather somewhere in
> 2.5)? Or was it already present in 2.4?

Well, the bug has been introduced by IBM in their firmware (SMM code).
;-) The patch only works it around. Functionally the changed code is the
same for your configuration.

If you are asking about the problematic code, then it's there since
2.3.x, so it's in 2.4, too. It's a part of the NMI watchdog support,
though it's used for ordinary timer interrupts for certain systems as

> When will this patch be merged into the 2.6-tree? I don't have to
> stress the impact of this problem on IBM servers as they are rendered
> quite useless.

Apparently there are problems with the workaround on certain AMD
Athlon-based systems. I suppose they need to be resolved somehow first.

> Which other IBM models are affected? Can I run 2.6.5 on my 345:s or
> 335:s? Do they use the same buggy SMM firmware?

Ask IBM. The reason is an incorrect handling of PIC (8259A) state

+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+ e-mail: macro@xxxxxxxxxxxxx, PGP key available +
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at