Re: [PATCH] x86 ACPI: Blacklist two HP machines with buggy BIOSes(Re: 2.6.27-rc8+ - first impressions)

From: Maciej W. Rozycki
Date: Mon Oct 06 2008 - 17:39:43 EST


On Mon, 6 Oct 2008, Andi Kleen wrote:

> The real reason is actually a workaround in the BIOS for problems
> in the older Linux code that caused duplicated timer interrupts. The
> old Linux would fall into "enable both IO-APIC and 8259" fallback mode
> and the resulted in duplicated timer events, which made everything unhappy.
> They instead configured the northbridge in a way that one of the inputs
> is ignored.

Hmm, working around Linux problems in the BIOS is a new and truly odd
concept to me. It's not that we are unresponsive or do not take
responsibility for our bugs, is it?

> You won't be able to DMI list it, that workaround is widely used
> in lots of different systems.

Well, perhaps, but the thermal trip point phenomenon seems unique to this
family of systems. The other aspects of the problem do not really matter
anymore as we seem to have addressed them robustly enough now.

Maciej
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