Messages in this thread | | | Date | Tue, 7 Oct 2008 06:42:37 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86 ACPI: Blacklist two HP machines with buggy BIOSes (Re: 2.6.27-rc8+ - first impressions) |
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* Maciej W. Rozycki <macro@linux-mips.org> wrote:
> > > 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. > > > > When you need DMI entries you clearly haven't. > > You can't just break a piece of hardware randomly (setting the > thermal trip points based on an interrupt mask of an I/O APIC input is > certainly beyond the ACPI spec), hide its documentation and still > demand it to be supported correctly, possibly hurting all the other > good equipment. Sorry -- you have to draw a line somewhere. [...]
agreed. This is a clear example of a complex and hard to track down BIOS bug - and even in this case we go out on a limb working it around.
The first approach to such problems is usually a DMI pattern based fix - they happen when we dont know the full scope of a particular problem yet but have a rough idea and want to react to bugs quickly.
PCI ID based quirks are preferred much more in the long run: DMI pattern matching does not scale as the DMI space is human-visible and hence changes frequently not for technical/hw-environment but for perception/PR reasons, hence it is far less reliable programmatically than the PCI ID space.
But PCI ID methods, while more intelligent, they lag behind a bit and depend on good cooperation with hw makers. As long as DMI pattern matches end up turning into PCI ID based approaches, like here, i'm not complaining as a maintainer ;)
Thanks Maciej for your excellent in-depth analysis of this issue, and for your many fixes in this area of code - you squashed many difficult, long-standing bugs in this space.
Ingo
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