RE: [discuss] Re: Please pull x86-64 bug fixes

Duran, Leo
2006-10-06T22:31:56Z

OK, lets' take K8 processor performance states (p-states) as an example:
BIOS, which should know 'best' about a given platform, needs to
communicate to the OS what 'voltage' (VID code) is correct for given
'frequency' (FID),
and it can do that via ACPI processor tables (_PSS). Otherwise, OS code
is left with having to manage a HUGE amount 'specifics' (processor
models), and endless driver revisions to account for new parts.

So, one can argue that there's merit on having ACPI, it's just a shame
when BIOS doesn't get it right! (thus the justification for lack of
'trust'... the same can probably be said about other BIOS issues, not
just ACPI)

Leo Duran

-----Original Message-----
From: Rafael J. Wysocki [mailto:rjw@sisk.pl]
Sent: Friday, October 06, 2006 5:01 PM
To: Linus Torvalds
Cc: Arjan van de Ven; Jeff Garzik; Andi Kleen; discuss@x86-64.org;
linux-kernel@vger.kernel.org
Subject: Re: [discuss] Re: Please pull x86-64 bug fixes

On Friday, 6 October 2006 18:07, Linus Torvalds wrote:
>
> On Fri, 6 Oct 2006, Arjan van de Ven wrote:
> >
> > we can do a tiny bit better than the current code; some chipsets
have
> > the address of the MMIO region stored in their config space; so we
can
> > get to that using the old method and validate the acpi code with
that.
>
> Yes. I think trusting ACPI is _always_ a mistake. It's insane. We
should
> never ask the firmware for any data that we can just figure out
ourselves.
>
> And we should tell all hardware companies that firmware tables are
stupid,
> and that we just want to know what the hell the registers MEAN!
>
> I've certainly tried to tell Intel that. I think they may even have
heard
> me occasionally.
>
> I can't understand why some people _still_ think ACPI is a good idea..

I violently agree.

Rafael

--
You never change things by fighting the existing reality.
R. Buckminster Fuller