From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266173AbUJEWPu (ORCPT ); Tue, 5 Oct 2004 18:15:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266127AbUJEWPt (ORCPT ); Tue, 5 Oct 2004 18:15:49 -0400 Received: from zero.aec.at ([193.170.194.10]:11535 "EHLO zero.aec.at") by vger.kernel.org with ESMTP id S266115AbUJEWPj (ORCPT ); Tue, 5 Oct 2004 18:15:39 -0400 To: Markus Lidel cc: linux-kernel@vger.kernel.org Subject: Re: question about MTRR areas on x86_64 References: <2M5w2-y8-3@gated-at.bofh.it> From: Andi Kleen Date: Wed, 06 Oct 2004 00:15:35 +0200 In-Reply-To: <2M5w2-y8-3@gated-at.bofh.it> (Markus Lidel's message of "Wed, 06 Oct 2004 00:00:22 +0200") Message-ID: User-Agent: Gnus/5.110003 (No Gnus v0.3) Emacs/21.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Markus Lidel writes: > > Could it be because the machine has too much memory, or is there a bug in the I2O driver? The problem comes from the BIOS who set up reg00 to be overlapping over other areas. The Linux MTRR driver cannot deal with overlapping MTRRs, in fact it is sometimes impossible because it could run out of registers or violate some of the MTRR restrictions. It's a long standing problem, eventual fix will be to get rid of MTRRs completely and only use PAT. But it needs a bit more work. -Andi