Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757370AbXJ3Rco (ORCPT ); Tue, 30 Oct 2007 13:32:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753591AbXJ3Rcf (ORCPT ); Tue, 30 Oct 2007 13:32:35 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:51274 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753552AbXJ3Rce (ORCPT ); Tue, 30 Oct 2007 13:32:34 -0400 Date: Tue, 30 Oct 2007 10:28:20 -0700 From: Arjan van de Ven To: Linus Torvalds Cc: Robert Hancock , Greg KH , Jesse Barnes , akpm@linux-foundation.org, ak@suse.de, rajesh.shah@intel.com, linux-kernel Subject: Re: pci-disable-decode-of-io-memory-during-bar-sizing.patch Message-ID: <20071030102820.47a6e365@laptopd505.fenrus.org> In-Reply-To: References: <200708151919.l7FJJfUE010966@imap1.linux-foundation.org> <200710251622.36773.jbarnes@virtuousgeek.org> <20071026025407.GA21408@kroah.com> <200710260959.46811.jbarnes@virtuousgeek.org> <20071027024140.GC29039@kroah.com> <47267232.3020506@shaw.ca> <20071030094756.779ac5c0@laptopd505.fenrus.org> Organization: Intel X-Mailer: Claws Mail 3.0.2 (GTK+ 2.12.1; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 53 On Tue, 30 Oct 2007 10:07:48 -0700 (PDT) Linus Torvalds wrote: > > > > The fact is, CONF1 style accesses are just safer, and *work*. > > > > I would suggest a slight twist then: use CONF1 *until* you're using > > something above 256, and then and only then switch to MMCONFIG from > > then on for all accesses. > > No. > > Maybe if you do it per-device, and only *after* probing (ie we have > seen multiple, and successful, accesses), but globally, absolutely > not. That would be useless. The bugs we have had in this area have > been exactly the kinds of things like "we don't know the real size of > the MMCONFIG areas" etc. sorry I wasn't very clear, I meant "per device". > > I could easily see device driver writers probing to see if something > works, and I absolutely don't think we should just automatically > enable MMCONFIG from then on. > > But maybe we could have a per-device flag that a driver *can* set. Ie > have the logic be: > > - use MMCONFIG if we have to (reg >= 256) > > OR > > - use MMCONFIG if the driver specifically asked us to something like int pci_enable_mmconfig(struct pci_dev *pdev) ? sounds like a very solid plan to me... > Maybe somebody inside Intel could just clarify the documentation, and > change it from "you're not supposed to mix" to "mix all you want". I'll see what I can do ;) -- If you want to reach me at my work email, use arjan@linux.intel.com For development, discussion and tips for power savings, visit http://www.lesswatts.org - 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/