Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936590AbXLQV5t (ORCPT ); Mon, 17 Dec 2007 16:57:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761339AbXLQV5h (ORCPT ); Mon, 17 Dec 2007 16:57:37 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:42278 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761447AbXLQV5f (ORCPT ); Mon, 17 Dec 2007 16:57:35 -0500 Date: Mon, 17 Dec 2007 22:56:59 +0100 From: Ingo Molnar To: Rene Herman Cc: Alan Cox , "David P. Reed" , "H. Peter Anvin" , Paul Rolland , Pavel Machek , Thomas Gleixner , linux-kernel@vger.kernel.org, Ingo Molnar , rol@witbe.net Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override. Message-ID: <20071217215658.GA4782@elte.hu> References: <20071217105744.GA14315@elte.hu> <4766684D.40202@gmail.com> <20071217130933.GB27992@elte.hu> <47667812.8050708@gmail.com> <47667A85.3080100@reed.com> <20071217143900.GA16604@elte.hu> <20071217161243.05c32df4@the-village.bc.nu> <4766E086.9090500@gmail.com> <20071217214139.GC22828@elte.hu> <4766EE79.90003@keyaccess.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4766EE79.90003@keyaccess.nl> 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: 1196 Lines: 27 * Rene Herman wrote: >>> Signed-off-by: Rene Herman >> >> hm, i see this as a step backwards from the pretty flexible patch >> that David already tested. (and which also passed a few hundred >> bootup tests on my x86 test-grid) > > Please see Alan's comment that udelay (and none) shouldn't yet be > provided as a choice. It opens race windows in drivers even when it > works in practice on most setups. The version with "udelay" and "none" > is not minimal, not low risk and certainly not .24 material. huh? By default we still use port 0x80. Any udelay is non-default and needs the user to explicitly switch to it. But it enables us to debug any suspected drivers by asking testers to: "please try this driver with io_delay=udelay, does it still work fine?". So those extra options are quite sensible. If you have any real technical arguments against that then please let us know. 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/