From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754178AbYBRWCS (ORCPT ); Mon, 18 Feb 2008 17:02:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752757AbYBRWCH (ORCPT ); Mon, 18 Feb 2008 17:02:07 -0500 Received: from terminus.zytor.com ([198.137.202.10]:41546 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752578AbYBRWCG (ORCPT ); Mon, 18 Feb 2008 17:02:06 -0500 Message-ID: <47BA002B.7070806@zytor.com> Date: Mon, 18 Feb 2008 14:01:15 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Rene Herman CC: "David P. Reed" , Thomas Gleixner , Ingo Molnar , Alan Cox , Dmitry Torokhov , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: use explicit timing delay for pit accesses in kernel and pcspkr driver References: <6gr00g$g7qpu0@smtp01.lnh.mail.rcn.net> <47B9ECE0.70000@keyaccess.nl> <47B9EDF1.5050404@zytor.com> <47B9F2EC.4070308@keyaccess.nl> <47B9FC3A.2010508@zytor.com> <47B9FFD5.6040801@keyaccess.nl> In-Reply-To: <47B9FFD5.6040801@keyaccess.nl> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Rene Herman wrote: > > Yes, but generally not any P5+ system is going to need the PIT delay in > the first place meaning it just doesn't matter. There were the VIA > issues with the PIC but unless I missed it not with the PIT. > Uhm, I'm not sure I believe that's safe. The PIT is particularly pissy in this case -- the semantics of the PIT are ill-defined if there hasn't been a PIT clock between two adjacent accesses, so I fully expect that there are chipsets out there which will do very bad things in this case. -hpa