From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758576Ab0ENXfR (ORCPT ); Fri, 14 May 2010 19:35:17 -0400 Received: from cpoproxy1-pub.bluehost.com ([69.89.21.11]:41200 "HELO outbound-mail-01.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754626Ab0ENXfN (ORCPT ); Fri, 14 May 2010 19:35:13 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=virtuousgeek.org; h=Received:Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References:X-Mailer:Mime-Version:Content-Type:Content-Transfer-Encoding:X-Identified-User; b=eQM6eOEcxjkdTMCuNbfRQnz7QUIguq5rLiQvIEsX7Yw5JdeuIPL1w6FgLcDONZrFxEzSmUhgUpadt/9AcP4UI+gvcbpV3lF9W3e9iqGkRHG9HxHG0jyuMVVgzCXcq2y/; Date: Fri, 14 May 2010 16:34:16 -0700 From: Jesse Barnes To: "H. Peter Anvin" Cc: Mike Travis , Bjorn Helgaas , Mike Habeck , Ingo Molnar , Thomas Gleixner , x86@kernel.org, Jacob Pan , Tejun Heo , LKML , Yinghai , "linux-pci@vger.kernel.org" , Myron Stowe Subject: Re: [Patch 1/1] x86 pci: Add option to not assign BAR's if not already assigned Message-ID: <20100514163416.0e940f64@virtuousgeek.org> In-Reply-To: <4BEDDD77.1050205@zytor.com> References: <4BEAF008.9030805@sgi.com> <201005131256.17997.bjorn.helgaas@hp.com> <4BEC5530.1000008@sgi.com> <201005131402.30759.bjorn.helgaas@hp.com> <20100514152509.3aeb37b4@virtuousgeek.org> <4BEDCFD9.7020202@sgi.com> <20100514154706.4f36f4ed@virtuousgeek.org> <4BEDDACD.9040704@zytor.com> <20100514162836.27e0325a@virtuousgeek.org> <4BEDDD77.1050205@zytor.com> X-Mailer: Claws Mail 3.7.5 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Identified-User: {10642:box514.bluehost.com:virtuous:virtuousgeek.org} {sentby:smtp auth 75.110.194.140 authed with jbarnes@virtuousgeek.org} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 May 2010 16:32:07 -0700 "H. Peter Anvin" wrote: > On 05/14/2010 04:28 PM, Jesse Barnes wrote: > > On Fri, 14 May 2010 16:20:45 -0700 > > "H. Peter Anvin" wrote: > > > >> On 05/14/2010 03:47 PM, Jesse Barnes wrote: > >>> > >>> Wow and they're using cards that want to use I/O space? Funky. It's > >>> too late to get this into 2.6.34, but that can't be what you were > >>> expecting... I don't see a problem with getting something like this in > >>> for 2.6.35. > >>> > >> > >> Most cards on the market provide I/O BARs as a convenience to legacy > >> BIOSes; they don't need the I/O BAR functionality from inside a > >> full-featured OS. There are a few, key, exceptions, mainly in the form > >> of legacy-interface devices like UARTs and VGA (note that VGA has its > >> own routing bits and is therefore unaffected by this problem.) > > > > Yeah, it's the "legacy" part that I'm questioning. I'm just lamenting > > that it's dying off so slowly... > > > > And yes, VGA is an unfortunate standard. > > > > I'm not lamenting that fact, because my experience is that what ends up > replacing it is often far worse. Consider UARTs -- no MMU dependencies > at all, can be accessed with four lines of assembly, and compare it to > EHCI debug port, the driver for which is over 900 lines in the Linux > kernel -- and that assumes that you're already in flat mode. Heh, you're so old and crufty! -- Jesse Barnes, Intel Open Source Technology Center