From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936527AbYEBUkr (ORCPT ); Fri, 2 May 2008 16:40:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933542AbYEBUkg (ORCPT ); Fri, 2 May 2008 16:40:36 -0400 Received: from mga03.intel.com ([143.182.124.21]:9400 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932948AbYEBUke (ORCPT ); Fri, 2 May 2008 16:40:34 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.27,428,1204531200"; d="scan'208";a="241290900" From: Jesse Barnes To: "Pallipadi, Venkatesh" Subject: Re: [git head] Should X86_PAT really default to yes? Date: Fri, 2 May 2008 13:40:24 -0700 User-Agent: KMail/1.9.9 Cc: "Frans Pop" , linux-kernel@vger.kernel.org, "Ingo Molnar" , "Packard, Keith" References: <200805022122.03576.elendil@planet.nl> <924EFEDD5F540B4284297C4DC59F3DEEFB8D3D@orsmsx423.amr.corp.intel.com> In-Reply-To: <924EFEDD5F540B4284297C4DC59F3DEEFB8D3D@orsmsx423.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200805021340.24987.jesse.barnes@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, May 02, 2008 12:37 pm Pallipadi, Venkatesh wrote: > >-----Original Message----- > >From: Frans Pop [mailto:elendil@planet.nl] > >Sent: Friday, May 02, 2008 12:22 PM > >To: linux-kernel@vger.kernel.org > >Cc: Pallipadi, Venkatesh; Ingo Molnar > >Subject: [git head] Should X86_PAT really default to yes? > > > >With X86_PAT enabled, when X is started I get about 40 lines > >(with varying > >addresses) like: > >kernel: Xorg:3358 /dev/mem expected mapping type write-back for > >807bf000-81000000, got uncached-minus These messages? They're coming from the kernel it looks like, from the map_devmem routine in pat.c. I'm not sure they're accurate though; for PCI regions /dev/mem is *supposed* to map with UC- and not WB, so maybe this function needs to be updated? > >And when X exits I get a bunch of lines like: > >kernel: Xorg:3349 freeing invalid memtype 80020000-8002a000 > > > >I also noticed artifacts (a band of about 2 cm high across the > >screen) after > >X goes to black but before the switch to VT1. This is just a transient issue during VT switch or server exit though, right? X functionality isn't affected, and your VTs work fine? If so, it might not be a PAT issue but just a different memory layout or something (and therefore it would really just be a cosmetic bug in the X driver). I really think PAT should be on by default; if you're running into real functional or performance problems we'd better get them fixed rather than disabling PAT... Thanks, Jesse