Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755606AbXJ3QwR (ORCPT ); Tue, 30 Oct 2007 12:52:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752877AbXJ3QwG (ORCPT ); Tue, 30 Oct 2007 12:52:06 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:39609 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752838AbXJ3QwE (ORCPT ); Tue, 30 Oct 2007 12:52:04 -0400 Date: Tue, 30 Oct 2007 09:47:56 -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: <20071030094756.779ac5c0@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> 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: 1361 Lines: 38 On Tue, 30 Oct 2007 08:15:46 -0700 (PDT) Linus Torvalds wrote: > > > On Mon, 29 Oct 2007, Robert Hancock wrote: > > > > The other possible workaround would be to avoid using MMCONFIG > > until the BAR sizing is done. > > The only sane solution is the one that people constantly seem to > ignore: > > - only use MMCONFIG if absolutely required by the access itself > > In other words, make the MMCONFIG code fall back on old-style > accesses for any register access to a word with reg+size <= 256. the problem is... you're not supposed to mix both types of accesses. > At that point, almost all the issues with mmconfig just go away, > BECAUSE NOBODY USES IT, so it doesn't matter if it's broken? > > 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. That should solve the spec issue (yes I know about specs, but this is one of those things that will bite us in the future if we're not careful) - 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/