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

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Date:	Sun, 12 Aug 2007 02:25:19 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Andi Kleen <ak@...e.de>
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 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.

You had obviously never actually tested this on x86.

> --- 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.

		Linus
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