Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757596AbXL3VKo (ORCPT ); Sun, 30 Dec 2007 16:10:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752095AbXL3VKf (ORCPT ); Sun, 30 Dec 2007 16:10:35 -0500 Received: from smtpq1.tilbu1.nb.home.nl ([213.51.146.200]:37123 "EHLO smtpq1.tilbu1.nb.home.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbXL3VKe (ORCPT ); Sun, 30 Dec 2007 16:10:34 -0500 Message-ID: <47780888.9070503@keyaccess.nl> Date: Sun, 30 Dec 2007 22:07:20 +0100 From: Rene Herman User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Ingo Molnar CC: Alan Cox , 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 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> <20071230204650.GA26120@elte.hu> In-Reply-To: <20071230204650.GA26120@elte.hu> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -1.0 (-) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1423 Lines: 29 On 30-12-07 21:46, Ingo Molnar wrote: > * 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'. On the other hand, the patch you just posted that makes io_delay=none the default _is_ blindly disabling. So that wasn't for consumption? io_delay=udelay additionally blindly disables the race-hiding effect the outb has on SMP and that Alan is seeing so many of. Should also wait for more driver review. Rene. -- 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/