Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756319AbXLWEpL (ORCPT ); Sat, 22 Dec 2007 23:45:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754800AbXLWEo6 (ORCPT ); Sat, 22 Dec 2007 23:44:58 -0500 Received: from smtp2.linux-foundation.org ([207.189.120.14]:35853 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754099AbXLWEo5 (ORCPT ); Sat, 22 Dec 2007 23:44:57 -0500 Date: Sat, 22 Dec 2007 20:44:37 -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: <476DE19F.5040702@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> <476DE19F.5040702@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: 1611 Lines: 41 On Sat, 22 Dec 2007, Jeff Garzik wrote: > > Jeff Garzik wrote: > > Maybe that day will never come, but it is nonetheless quite possible without > > today's PCI Express spec for this to happen. > > er, s/without/within/ You're talking specs. I'm talking machines. I agree with you 100% that as per specs, you need to support MMCONFIG, because anything can happen. As per *reality*, though, machines sold today simply don't need it. So there is no upside, and there is definitely downside. I want to limit that downside. Right now, the easiest way to limit it seems to be to say that those (very very few) drivers that actually care could enable it. That way, we automatically limit it to only those machines that have hardware that cares. And yes, if you want the capability following to notice automatically when capabilities really do go into the 0x100+ range, that's fine. I suspect that there aren't really very many cards that do that (because they wouldn't work with WinXP etc), so I doubt it will actually enable MMCONFIG for any noticeable amount of hardware sold today. Which is exactly what I want. I do *not* want to enable MMCONFIG unless it is shown to actually be needed. And no, "specs" do not show it is needed. MMCONFIG is needed depending on the actual *hardware* the kernel runs on, not based on some external specs. 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/