From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752387Ab0EaLM2 (ORCPT ); Mon, 31 May 2010 07:12:28 -0400 Received: from relay3.sgi.com ([192.48.152.1]:40007 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751640Ab0EaLM1 (ORCPT ); Mon, 31 May 2010 07:12:27 -0400 Message-ID: <4C039980.3020608@sgi.com> Date: Mon, 31 May 2010 04:12:00 -0700 From: Mike Travis User-Agent: Thunderbird 2.0.0.24 (X11/20100411) MIME-Version: 1.0 To: "H. Peter Anvin" CC: Ingo Molnar , Thomas Gleixner , x86@kernel.org, Jesse Barnes , Bjorn Helgaas , Jacob Pan , Tejun Heo , Mike Habeck , LKML Subject: Re: [Patch 1/1] x86 pci: Add option to not assign BAR's if not already assigned References: <4BEAF008.9030805@sgi.com> <4BFFF517.6040401@sgi.com> <4BFFF6B8.30005@zytor.com> <4BFFF8F8.1070502@sgi.com> <4C0021DC.60608@zytor.com> In-Reply-To: <4C0021DC.60608@zytor.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org H. Peter Anvin wrote: > On 05/28/2010 10:10 AM, Mike Travis wrote: >> >> H. Peter Anvin wrote: >>> On 05/28/2010 09:53 AM, Mike Travis wrote: >>>> Any further consideration for this patch, or has it been rejected? >>> Well, it's really up to Jesse, but as far as I can see, this patch is a >>> net loss of functionality and doesn't actually add anything. Without >>> this patch, some resources that were not assigned by BIOS will be >>> unreachable. With this patch, *all* resources that were not assigned by >>> BIOS will be unreachable... >>> >>> -hpa >>> >> Apparently you're missing the point of the patch? The patch is needed >> because BIOS is purposely not assigning I/O BAR's to devices that won't >> use them, freeing up the resource for devices that do need them. Where >> is the "all" resources that are not reachable? >> > > No, the patch isn't needed for those. > > Without your patch: > > - Devices assigned by BIOS remain assigned; > - Devices not assigned by BIOS get assigned until address space > exhausted. > > With your patch: > > - Devices assigned by BIOS remain assigned; > - Devices not assigned by BIOS never get assigned at all. > > What am I missing here? > > -hpa > BIOS still assigns the MMIO BAR's so the devices are alive.