Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964813AbWE3XGa (ORCPT ); Tue, 30 May 2006 19:06:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964811AbWE3XGa (ORCPT ); Tue, 30 May 2006 19:06:30 -0400 Received: from mailgw.cvut.cz ([147.32.3.235]:21713 "EHLO mailgw.cvut.cz") by vger.kernel.org with ESMTP id S964808AbWE3XG2 (ORCPT ); Tue, 30 May 2006 19:06:28 -0400 Message-ID: <447CCFF2.30207@vc.cvut.cz> Date: Wed, 31 May 2006 01:06:26 +0200 From: Petr Vandrovec User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.7.12) Gecko/20060205 Debian/1.7.12-1.1 X-Accept-Language: cs, en MIME-Version: 1.0 To: Jeremy Fitzhardinge CC: konradr@us.ibm.com, Jeremy Fitzhardinge , Linux Kernel Mailing List , arjan@linux.intel.com, linux-acpi@vger.kernel.org Subject: Re: ThinkPad X60: PCI: BIOS Bug: MCFG area is not E820-reserved (MCFG is in ACPI NVS) References: <447C9F19.5000105@goop.org> <20060530204112.GA22031@andromeda.dapyr.net> <1149025621.25497.9.camel@jeremy.eng.hq.xensource.com> In-Reply-To: <1149025621.25497.9.camel@jeremy.eng.hq.xensource.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1785 Lines: 42 Jeremy Fitzhardinge wrote: > On Tue, 2006-05-30 at 16:41 -0400, konradr@us.ibm.com wrote: > >>On Tue, May 30, 2006 at 12:38:01PM -0700, Jeremy Fitzhardinge wrote: >> >>>[snip] >>> >>>So the MCFG entry is in the ACPI NVS region of the E820 table. Is this >>>bad? >> >>Not at all. The ACPI v3.0 specs mentions that: >> >>"ACPI NVS Memory. This range of addresses is in use or reserve by >>the system and must not be used by the operating system. This >>range is required to be saved and restored across an NVS sleep." > > > I actually misread the tables. It appears that MCFG (at 0x7f6e2e36) is > in ACPI Data (7f6d0000 - 7f6e3000). include/asm-i386/e820.h says that > memory marked as "E820_ACPI" can be reused as normal memory once the > ACPI tables have been read. > > Doesn't this mean that the MCFG memory could end up being used as > general system memory? That seems bad if MCFG memory is some kind of > MMIO space. Or is the comment simply wrong? Address where MCFG table lives is not important. What is important (and checked) is address of MMCONFIG reported by MCFG table... Unfortunately code does not bother with printing that address :-( Another problem is that code has hardcoded that MMCONFIG area is 256MB large. Unfortunately for the code PCI specification allows any power of two between 2MB and 256MB if vendor knows that such amount of busses (from 2 to 128) will be sufficient for system. With notebook it is quite possible that not full 8 bits are implemented for MMCONFIG bus number. Petr - 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/