From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933202Ab2GFSMg (ORCPT ); Fri, 6 Jul 2012 14:12:36 -0400 Received: from mail-ey0-f202.google.com ([209.85.215.202]:54227 "EHLO mail-ey0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932610Ab2GFSMb (ORCPT ); Fri, 6 Jul 2012 14:12:31 -0400 Date: Fri, 6 Jul 2012 12:06:35 -0600 From: Bjorn Helgaas To: Jiang Liu Cc: Bill Unruh , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org Subject: Re: [Bug 43331] Re: Bug on bootup of Linux kernel on Panasonic Toughbook S10 Message-ID: <20120706180635.GB17196@google.com> References: <4FC988CF.5030602@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FC988CF.5030602@gmail.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 02, 2012 at 11:30:23AM +0800, Jiang Liu wrote: > ... address range 0xfed98000-0xfed9ffff has been reserved by motherboard > device(PNP0C02). I guess that BIOS has assigned address "0xfed98000" to > 0000:00:04.0 for thermal management functionality. The BAR0 of > 0000:00:04.0 may be locked down (can't be changed by OS) because the ACPI > BIOS may have dependency on the assigned address ranges. I don't think the BAR can be completely read-only. If it were, we wouldn't have any way to determine its size. We believe it is 32K in size: pci 0000:00:04.0: reg 10: [mem 0xfed98000-0xfed9ffff 64bit] so we should have written 0xffffffff to the low 32 bits of the BAR and read back 0xffff8004 (32K = 2^15, so the low-order 15 bits should be read-only, including the prefetchable bit (0), the type bits (10 for 64-bit), and the memory space indicator (0)). Can you experiment with setting that BAR manually, e.g., by running these commands as root: # setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 # setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 # setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1 That's basically what the kernel does in pci_update_resource(), so this will likely fail, too. In __pci_read_base(), where we size the BAR, we disable decoding first, which we *don't* do in pci_update_resource(). So if the above doesn't work, can you try this: # setpci -s 00:04.0 COMMAND BASE_ADDRESS_0 BASE_ADDRESS_1 # setpci -s 00:04.0 COMMAND=0 # setpci -s 00:04.0 BASE_ADDRESS_0=0xdfa00000 # setpci -s 00:04.0 BASE_ADDRESS_0 BASE_ADDRESS_1