Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751502AbZJKHlh (ORCPT ); Sun, 11 Oct 2009 03:41:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751426AbZJKHlf (ORCPT ); Sun, 11 Oct 2009 03:41:35 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:42427 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbZJKHle (ORCPT ); Sun, 11 Oct 2009 03:41:34 -0400 Date: Sun, 11 Oct 2009 09:40:45 +0200 From: Ingo Molnar To: Arjan van de Ven Cc: Thomas Schlichter , linux-kernel@vger.kernel.org, Thomas Hellstrom , Yinghai Lu , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [RFC Patch] use MTRR for write combining if PAT is not available Message-ID: <20091011074045.GA6555@elte.hu> References: <200910100322.36857.thomas.schlichter@web.de> <4AD00C89.3000503@linux.intel.com> <200910101031.15620.thomas.schlichter@web.de> <4AD0ABFF.1020209@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4AD0ABFF.1020209@linux.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1265 Lines: 33 * Arjan van de Ven wrote: > Thomas Schlichter wrote: > >> Hmm, my CPU (VIA Nano) seems to support PAT, but Ubuntu disables this >> feature in its kernel config. I'm using 9.04, but even 9.10 will have PAT >> disabled: > > that sounds like a bad idea. But to each distro their own I suppose. > > >> >> http://kernel.ubuntu.com/git?p=ubuntu/ubuntu- >> karmic.git;a=blob;f=debian.master/config/config.common.ubuntu;h=a43cbabd02bfdf5412de6fea232db86aa5d3e742;hb=HEAD > >> So, convincing Ubuntu to enable PAT would be a workaround, but I think >> the problem would still exist and should be fixed. > > I think it's time to get rid of CONFIG_PAT at all.. and just have it > be there. Making 10+ year old CPU features that are essential > functionality a config option... ... not a good idea to be honest. Mind sending a patch that makes the configurability of PAT dependent on EMBEDDED or so? There's still the nopat boot option so it can still be configured by a distro if it wishes to. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/