Re: [patches] [patch 3/5] x86: Add PCI extended config space access for AMD Barcelona

Andreas Herrmann
2007-09-05T16:13:36Z

On Wed, Sep 05, 2007 at 01:05:25PM +0200, Arne Georg Gleditsch wrote:
> "H. Peter Anvin" <hpa@zytor.com> writes:
> > You're missing the point. How will the PCI bus transactions be
> > different when using MMCONFIG versus your extended CF8 version?
>
> Conceivably this is useful if the IO hub does not support MMCONFIG
> accesses. The AMD 8111 does not, as far as I can see. At least I
> have an Opteron system where MMCONFIG is not supported, and I assume
> it's because the 8111 doesn't provide it. I don't know if this is
> going to be a realistic scenario for Barcelona systems.
>
> --
> Arne.

Not sure how many AMD 8111 based systems are out there which are
upgradeable to Barcelona.

I guess the BIOS won't setup MCFG for systems with 8111/8131
because both lack ECS MMIO Base Address Register.
(Because 8111 and 8131 are not Mode2-PCI-X and PCI-express
capable.)

So if such a board is upgradeable, the way to access extended
config space of the northbridge functions is to use CF8/CFC
ECS access.

Regards,

Andreas

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