Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754501AbYAMEnm (ORCPT ); Sat, 12 Jan 2008 23:43:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753310AbYAMEnf (ORCPT ); Sat, 12 Jan 2008 23:43:35 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:43186 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753017AbYAMEne (ORCPT ); Sat, 12 Jan 2008 23:43:34 -0500 Date: Sat, 12 Jan 2008 20:42:48 -0800 From: Arjan van de Ven To: tcamuso@redhat.com Cc: Ivan Kokshaysky , Greg KH , Matthew Wilcox , Linus Torvalds , Greg KH , linux-kernel@vger.kernel.org, Jeff Garzik , linux-pci@atrey.karlin.mff.cuni.cz, Benjamin Herrenschmidt , Martin Mares , Loic Prylli , Prarit Bhargava , "Chumbalkar, Nagananda" , "Schoeller, Patrick (Linux - Houston, TX)" , Bhavana Nagendra Subject: Re: [Patch v2] Make PCI extended config space (MMCONFIG) a driver opt-in Message-ID: <20080112204248.29abb1dd@laptopd505.fenrus.org> In-Reply-To: <47896B3B.2000108@redhat.com> References: <20080111204228.GP18741@parisc-linux.org> <20080111211753.GR18741@parisc-linux.org> <20080111213803.GS18741@parisc-linux.org> <20080111235856.GA16079@jurassic.park.msu.ru> <20080112002638.GA18710@kroah.com> <20080112144030.GA19279@jurassic.park.msu.ru> <20080112094557.71f5382a@laptopd505.fenrus.org> <20080112214911.GA20102@jurassic.park.msu.ru> <20080112150120.05f93768@laptopd505.fenrus.org> <47895767.3090503@redhat.com> <20080112164006.6f6f7bc2@laptopd505.fenrus.org> <47896B3B.2000108@redhat.com> 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1928 Lines: 50 On Sat, 12 Jan 2008 20:36:59 -0500 Tony Camuso wrote: > Thanks, Arjan. > > The problem we have been experiencing has to do with Northbridges, > not with devices. correct for now. HOWEVER, and this is the point Linus has made several times: Just about NOBODY has devices that need the extended config space. At all. So making this opt-in for devices allows our users to boot and use their system if they are in the majority that has no need for even getting close to this mess. > > As far as the device is concerned, after the Northbridge translates > the config access into PCI bus cycles, the device has no idea what > mechanism drove the Northbridge to the translation. Wanne bet there'll be devices that screw this up? THere's devices that even screwed up the 64-256 region after all. > The patch I devised concerned itself with Northbridges and separated > MMCONFIG-compliant buses from those that could not handle MMCONFIG. THis kind of patchup has been going on for the better part of a year (well 2 years) by now and it's STILL NOT ENOUGH, as you can see by the more patchups that have been proposed as "alternative" to my approach. > > In my humble opinion, Port IO config access is here to stay, having > been defined as an architected mechanism in the PCI 2.1 spec. > > This is most especially true for x86. > > In other words, for x86, I don't think we need to worry about Port > IO config access ever going away at all. You're wrong there. Sad to say, but you're wrong there. -- 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/