Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755473AbYGWS5S (ORCPT ); Wed, 23 Jul 2008 14:57:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753508AbYGWS5E (ORCPT ); Wed, 23 Jul 2008 14:57:04 -0400 Received: from g5t0008.atlanta.hp.com ([15.192.0.45]:18352 "EHLO g5t0008.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754170AbYGWS5D (ORCPT ); Wed, 23 Jul 2008 14:57:03 -0400 From: Bjorn Helgaas To: "Fabio Comolli" Subject: Re: New conflict message in latest GIT Date: Wed, 23 Jul 2008 12:56:42 -0600 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) Cc: "Linux Kernel Mailing List" , Rene Herman , Andrew Morton , Thomas Renninger , Jean Delvare References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200807231256.42743.bjorn.helgaas@hp.com> X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1758 Lines: 38 On Tuesday 22 July 2008 12:56:36 pm Fabio Comolli wrote: > Linus' GIT tree 2.6.26-05752-g93ded9b shows this message: > > i801_smbus 0000:00:1f.3: PCI INT B -> GSI 19 (level, low) -> IRQ 19 > ACPI: I/O resource 0000:00:1f.3 [0x18e0-0x18ff] conflicts with ACPI > region SMBI [0x18e0-0x18ef] > ACPI: Device needs an ACPI driver > > There is no equivalent in 2.6.26 or previous kernels. The "ACPI: I/O resource ... conflicts with ..." message was added by Thomas: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=df92e695998e1bc6e426a840eb86d6d1ee87e2a5 That conflict checking infrastructure was in 2.6.26, but Jean's change to make the i801_smbus driver use it didn't happen until about a week ago: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=54fb4a05af0a4b814e6716cfdf3fa97fc6be7a32 The message is telling us that the i801_smbus driver thinks it owns the 0x18e0-0x18ff region, but there's also an ACPI opregion that references that region. There's no coordination between ACPI and the i801_smbus driver, so there may be issues where nearly simultaneous accesses cause incorrect behavior, e.g,. one may read the wrong value from a temperature sensor. That, of course, can lead to more serious things like unintended machine shutdowns. I don't have any ideas about how to address this. I think Thomas's intent was to collect better information for unreproducible bugs. (Maybe this sort of conflict should even set a taint flag?) Bjorn -- 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/