Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751954AbYANOrS (ORCPT ); Mon, 14 Jan 2008 09:47:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750957AbYANOrJ (ORCPT ); Mon, 14 Jan 2008 09:47:09 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:59092 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750867AbYANOrI (ORCPT ); Mon, 14 Jan 2008 09:47:08 -0500 Date: Mon, 14 Jan 2008 06:46:14 -0800 From: Arjan van de Ven To: tcamuso@redhat.com Cc: Alan Cox , 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: <20080114064614.22081ff3@laptopd505.fenrus.org> In-Reply-To: <478B5D0D.7060808@redhat.com> References: <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> <20080112204248.29abb1dd@laptopd505.fenrus.org> <478A075F.7010503@redhat.com> <20080113090311.0a9a1db5@laptopd505.fenrus.org> <478A8268.6020107@redhat.com> <20080114005434.48340f84@lxorguk.ukuu.org.uk> <20080113173331.617ac935@laptopd505.fenrus.org> <478AD713.8060204@redhat.com> <20080113210501.4584e4d2@laptopd505.fenrus.o! rg> <478B5D0D.7060808@redhat.com> Organization: Intel X-Mailer: Claws Mail 3.2.0 (GTK+ 2.12.3; 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: 1629 Lines: 42 On Mon, 14 Jan 2008 08:01:01 -0500 Tony Camuso wrote: > Arjan van de Ven wrote: > > On Sun, 13 Jan 2008 22:29:23 -0500 > > Tony Camuso wrote: > > > >> . There is no need to provide different PCI config access > >> mechanisms at device granularity, since the PCI config access > >> mechanism between the CPU and the Northbridge is opaque to > >> the devices. PCI config mechanisms only need to differ at > >> the Northbridge level. > > > > This ignores the "lets make it not matter for the 99% of the users" > > case. > > I don't understand. That;s clear :) > If we're going to differentiate MMCONFIG from > some other access mechanism, it only needs to be done at the > Northbridge level. Devices are electrically ignorant of the protocol > used between CPU and Northbridge to get the Northbridge to assert > config cycles on the bus. Again this is about having systems that don't need extended config space not use it. At all. The only way to do that is have the drivers say they need it, and not use it otherwise. It has NOTHING to do with how things are wired up. It's pure a kernel level policy decision about whether to use extended config space AT ALL. -- 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/