linux-kernel - Re: [PATCH] [1/12] x86: Work around mmio config space quirk on AMD Fam10h

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Message-Id: <200708121203.23741.ak@suse.de>
Date:	Sun, 12 Aug 2007 12:03:23 +0200
From:	Andi Kleen <ak@...e.de>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	dean@...tic.org, patches@...-64.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [1/12] x86: Work around mmio config space quirk on AMD Fam10h

On Sunday 12 August 2007 11:25, Linus Torvalds wrote:
> On Thu, 9 Aug 2007, Andi Kleen wrote:
> > Some broken devices have been discovered to require %al/%ax/%eax
> > registers for MMIO config space accesses.  Modify mmconfig.c to use these
> > registers explicitly (rather than modify the global readb/writeb/etc
> > inlines).
> >
> > AK: also changed i386 to always use eax
> > AK: moved change to extended space probing to different patch
> > AK: reworked with inlines according to Linus' requirements.
> > AK: improve comments.
> >
> > Signed-off-by: dean gaudet <dean@...tic.org>
> > Signed-off-by: Andi Kleen <ak@...e.de>
>
> Damn you, Andi.

Thanks for the kind words.

> You had obviously never actually tested this on x86.

Hmm, it booted on my i386 test box but it's possible it didn't use MCFG.

>
> > --- linux.orig/arch/i386/pci/mmconfig.c
> > +++ linux/arch/i386/pci/mmconfig.c
> > -		writeb(value, mmcfg_virt_addr + reg);
> > +		mmio_config_writeb(mmcfg_virt_addr, value);
>
> Notice something missing here? The new code cannot work on any machine
> that actually uses mmio cfg.

Sigh. Ok I assume you already reverted and I'll send a new one.

-Andi
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