Re: [patch] fix ACPI boot regression (was: Re: Linux 2.6.25-rc5)

From: Ingo Molnar
Date: Mon Mar 10 2008 - 13:24:59 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Mon, 10 Mar 2008, Ingo Molnar wrote:
> >
> > so zero-extending the result in the PCI-BIOS read routine fixes the
> > regression on my laptop. ( It might fix some other long-standing
> > issues we had with PCI-BIOS during the past decade ... ) Both 8-bit
> > and 16-bit accesses were buggy.
>
> Oh, wow. That must have been there forever, but very few people
> probably ever cared.
>
> And why is your laptop using the BIOS routines anyway? Or was that
> just a result of your randconfig having turned off the sane config
> access routines?

yeah, randconfig generated this:

CONFIG_PCI=y
CONFIG_PCI_GOBIOS=y
# CONFIG_PCI_GOMMCONFIG is not set
# CONFIG_PCI_GODIRECT is not set
# CONFIG_PCI_GOANY is not set
CONFIG_PCI_BIOS=y

which forced the PCI code into the BIOS access method on this otherwise
modern system. I disable some of the really-known-to-be-broken .config
options in randconfig - but i still bravely keept CONFIG_GO_PCIBIOS in
the randomized space, which triggered this.

On another box, which has a different BIOS, this bug never happened, in
tens of thousands of bootup tests.

Ingo
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