Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756167AbXLWEkx (ORCPT ); Sat, 22 Dec 2007 23:40:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753355AbXLWEkq (ORCPT ); Sat, 22 Dec 2007 23:40:46 -0500 Received: from smtp2.linux-foundation.org ([207.189.120.14]:43836 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752688AbXLWEkp (ORCPT ); Sat, 22 Dec 2007 23:40:45 -0500 Date: Sat, 22 Dec 2007 20:40:14 -0800 (PST) From: Linus Torvalds To: Jeff Garzik cc: Arjan van de Ven , linux-kernel@vger.kernel.org, gregkh@suse.de, linux-pci@atrey.karlin.mff.cuni.cz, Benjamin Herrenschmidt Subject: Re: [patch] Make MMCONFIG space (extended PCI config space) a driver opt-in issue In-Reply-To: <476DE07A.4000204@garzik.org> Message-ID: References: <20071222043139.0cd59804@laptopd505.fenrus.org> <476D1D16.5090703@garzik.org> <20071222064719.73fdd9a4@laptopd505.fenrus.org> <476DB95F.3090801@garzik.org> <476DE07A.4000204@garzik.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1312 Lines: 30 On Sat, 22 Dec 2007, Jeff Garzik wrote: > > It should be self-evident that mmconfig doesn't work on old hardware, is not > needed on old hardware, should not be turned on for old hardware, and in > general should never disturb old hardware. .. but it does. How do you figure out when to turn it off? By "old hardware" I don't mean stuff from the last century, that generally doesn't even *have* MMCONFIG. I mean the stuff you can buy *today*, which will be old by the time people really start _needing_ MMCONFIG. The fact is, 99% of the hardware you buy *today* has absolutely zero need for extended PCI config access. In fact, I would not be surprised at all if most hardware sold today generally doesn't have *any* devices that even have config registers in the 0x100+ range. So those are the kinds of machines we want to protect from blowing up. Stuff that isn't sold with Vista, and has never been tested (or where vista does some work-arounds we don't even know about - somebody was mentioning things like looking at the BIOS date etc). Linus -- 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/