Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757995AbXL3QGp (ORCPT ); Sun, 30 Dec 2007 11:06:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756369AbXL3QGj (ORCPT ); Sun, 30 Dec 2007 11:06:39 -0500 Received: from one.firstfloor.org ([213.235.205.2]:41931 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755790AbXL3QGi (ORCPT ); Sun, 30 Dec 2007 11:06:38 -0500 Date: Sun, 30 Dec 2007 17:08:17 +0100 From: Andi Kleen To: Ingo Molnar Cc: Andi Kleen , Linus Torvalds , Rene Herman , dpreed@reed.com, Islam Amer , Alan Cox , hpa@zytor.com, Pavel Machek , Ingo Molnar , Thomas Gleixner , Linux Kernel Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override Message-ID: <20071230160817.GB32752@one.firstfloor.org> References: <477711DC.5030800@keyaccess.nl> <20071230124852.GA30836@one.firstfloor.org> <20071230130544.GB16946@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071230130544.GB16946@elte.hu> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1293 Lines: 31 On Sun, Dec 30, 2007 at 02:05:44PM +0100, Ingo Molnar wrote: > > * Andi Kleen wrote: > > > > drivers that then are shown to really need it could use their *own* > > > ports. > > > > The i8259 driver uses it and it is known to be needed on some old > > chipsets. But it doesn't really have any "own" ports to use afaik. > > we'll solve that via an i8259-specific quirk. That is a lot cleaner and > maintainable than the current generic, always-enabled "opt out" > port-0x80 quirk. You mean using pci quirks + udelay? Will be probably challenging to collect PCI-IDs for that. And there might be old systems needing it without PCI. They likely won't have DMI either. In theory you could make it a DMI year cut off of course (and assume old if no DMI, although that happens occasionally with new systems too); but that is generally considered ugly. I don't think it's a big problem to keep delays of some form by default in 8259 -- people who care about performance should be definitely using APIC mode instead. -Andi -- 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/