Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765561AbXLON1z (ORCPT ); Sat, 15 Dec 2007 08:27:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752570AbXLON1r (ORCPT ); Sat, 15 Dec 2007 08:27:47 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:57808 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752807AbXLON1q (ORCPT ); Sat, 15 Dec 2007 08:27:46 -0500 Date: Sat, 15 Dec 2007 14:27:25 +0100 From: Ingo Molnar To: Rene Herman Cc: "H. Peter Anvin" , "David P. Reed" , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , Rene Herman , Pavel Machek , Alan Cox Subject: Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80 on some AMD64x2 laptops, etc. Message-ID: <20071215132725.GA23166@elte.hu> References: <1184218962.12353.209.camel@chaos> <46964352.7040301@reed.com> <1184253339.12353.223.camel@chaos> <469697C6.50903@reed.com> <1184274754.12353.254.camel@chaos> <4761F193.7090400@reed.com> <20071214131502.GA14359@elte.hu> <4762C551.5070003@zytor.com> <20071215074358.GD12110@elte.hu> <4763891A.3010004@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4763891A.3010004@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean 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=3.2.3 -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: 936 Lines: 24 * Rene Herman wrote: > The issue is -- how do you safely replace the outb pre-loops_per_jiffy > calibration? I'm currently running with the attached hack (not > submitted, only for 32-bit and discussion) the idea of which might be > the best we can do? how about doing a known-NOP chipset cycle? For example: inb(PIC_SLAVE_IMR) ? I.e. instead of trying to find an unused port, lets try to find a known-used platform register that has no side-effects if read. Use it unconditionally during early bootup and change it to an udelay after calibration. (or use it after early bootup too if a boot parameter has been specified) Or something like this. 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/