Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759872AbYALVss (ORCPT ); Sat, 12 Jan 2008 16:48:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752026AbYALVsl (ORCPT ); Sat, 12 Jan 2008 16:48:41 -0500 Received: from jurassic.park.msu.ru ([195.208.223.243]:57590 "EHLO jurassic.park.msu.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750888AbYALVsl (ORCPT ); Sat, 12 Jan 2008 16:48:41 -0500 Date: Sun, 13 Jan 2008 00:49:11 +0300 From: Ivan Kokshaysky To: Arjan van de Ven Cc: 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 , Tony Camuso , Loic Prylli Subject: Re: [Patch v2] Make PCI extended config space (MMCONFIG) a driver opt-in Message-ID: <20080112214911.GA20102@jurassic.park.msu.ru> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080112094557.71f5382a@laptopd505.fenrus.org> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1391 Lines: 29 On Sat, Jan 12, 2008 at 09:45:57AM -0800, Arjan van de Ven wrote: > btw this is my main objection to your patch; it intertwines the conf1 > and mmconfig code even more. There is nothing wrong with it; please realize that mmconf and conf1 are just different cpu-side interfaces. Both produce precisely the *same* bus cycles as far as the lower 256-byte space is concerned. > When (and I'm saying "when" not "if") systems arrive that only have > MMCONFIG for some of the devices, we'll have to detangle this again, > and I'm really not looking forward to that. MMCONFIG for *some* of the devices? This doesn't sound realistic from technical point of view. MMCONFIG-only systems? Sure. I really hope to see these. But it won't be PC-AT architecture anymore. It has to be something like alpha, for instance, fully utilizing the 64-bit address space, and we'll have to have the whole low-level PCI infrastructure completely different for these future platforms anyway. Right now, each and every x86 chipset *does* require working conf1 just in order to set up the mmconf aperture. It's the very fundamental thing, sort of design philosophy. Ivan. -- 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/