Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758151AbXL3UzG (ORCPT ); Sun, 30 Dec 2007 15:55:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754901AbXL3Uyz (ORCPT ); Sun, 30 Dec 2007 15:54:55 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:38911 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034AbXL3Uyx (ORCPT ); Sun, 30 Dec 2007 15:54:53 -0500 Date: Sun, 30 Dec 2007 21:46:50 +0100 From: Ingo Molnar To: Alan Cox Cc: Rene Herman , Linus Torvalds , dpreed@reed.com, Islam Amer , hpa@zytor.com, Pavel Machek , Ingo Molnar , Andi Kleen , Thomas Gleixner , Linux Kernel Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override Message-ID: <20071230204650.GA26120@elte.hu> References: <477711DC.5030800@keyaccess.nl> <20071230144700.78f4605c@the-village.bc.nu> <20071230152835.GX16946@elte.hu> <4777BDA5.4050203@keyaccess.nl> <20071230160751.GB26221@elte.hu> <4777C6E8.7060202@keyaccess.nl> <20071230170612.GA16502@elte.hu> <20071230182937.40f2adcf@the-village.bc.nu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071230182937.40f2adcf@the-village.bc.nu> 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: 1274 Lines: 26 * Alan Cox wrote: > > So the current plan is to go with an io_delay=udelay default in v2.6.25, > > to give this a migration window, and io_delay=none in v2.6.26 [and a > > complete removal of arch/x86/kernel/io_delay.c], once the _p() uses are > > fixed up. This is gradual enough to notice any regressions we care about > > and also makes it nicely bisectable and gradual. > > You will break systems if you blindly go around disabling _p delays > for ISA and LPC bus devices. The DEC Hinote laptops for example are > well known for requiring the correct ISA and other keyboard controller > delays. I don't expect anyone to test with a hinote or see it until it > hits Debian or similar 'low resource' friendly devices. well, using io_delay=udelay is not 'blindly disabling'. io_delay=none would be the end goal, once all _p() API uses are eliminated by transformation. In drivers/ alone that's more than 1000 callsites, so it's quite frequently used, and wont go away overnight. 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/