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Message-ID: <4822F4A1.2030602@keyaccess.nl>
Date: Thu, 08 May 2008 14:40:01 +0200
From: Rene Herman <rene.herman@keyaccess.nl>
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To: Andi Kleen <andi@firstfloor.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>,
       "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
       Adrian Bunk <bunk@kernel.org>, Yinghai Lu <yhlu.kernel@gmail.com>,
       Ingo Molnar <mingo@elte.hu>,
       Linux Kernel <linux-kernel@vger.kernel.org>, akpm@linux-foundation.org,
       Pavel Machek <pavel@suse.cz>
Subject: Re: [PATCH] x86: introduce a new Linux defined feature flag for PAT
 support
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On 08-05-08 12:19, Andi Kleen wrote:

>> Use a new Linux defined X86_FEATURE_PAT_GOOD feature flag to
> 
> Better would be PAT_TESTED or PAT_RANDOMLY_APPROVED. Most of these
> CPUs without PAT_GOOD have actually perfectly good PAT, as Windows
> proves every day.
> 
> The main flaw in all of this of course is that there is no procedure
> to test CPUs which do not have the flag set yet.

Quite. And hiding the fact that the CPU _should_ have perfectly good
PAT doesn't help any at all. The discussion turned into a mini-flame
war enough that now noone would even consider backing down, but this
current PAT setup just sucks plain and simple.

Rene.