Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754905AbYJGEnM (ORCPT ); Tue, 7 Oct 2008 00:43:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750836AbYJGEm6 (ORCPT ); Tue, 7 Oct 2008 00:42:58 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:59028 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbYJGEm5 (ORCPT ); Tue, 7 Oct 2008 00:42:57 -0400 Date: Tue, 7 Oct 2008 06:42:37 +0200 From: Ingo Molnar To: "Maciej W. Rozycki" Cc: Andi Kleen , Linus Torvalds , "Rafael J. Wysocki" , Dmitry Torokhov , linux-kernel@vger.kernel.org, Andrew Morton , Len Brown , Jason Vas Dias Subject: Re: [PATCH] x86 ACPI: Blacklist two HP machines with buggy BIOSes (Re: 2.6.27-rc8+ - first impressions) Message-ID: <20081007044237.GA6355@elte.hu> References: <200810060029.42471.rjw@sisk.pl> <20081006062235.GA2808@amd.corenet.prv> <200810061159.30103.rjw@sisk.pl> <20081006150055.GA16930@elte.hu> <87tzbpmocm.fsf@basil.nowhere.org> <20081006231002.GN3180@one.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2021 Lines: 44 * Maciej W. Rozycki wrote: > > > Well, perhaps, but the thermal trip point phenomenon seems unique > > > to this family of systems. The other aspects of the problem do > > > not really matter anymore as we seem to have addressed them > > > robustly enough now. > > > > When you need DMI entries you clearly haven't. > > You can't just break a piece of hardware randomly (setting the > thermal trip points based on an interrupt mask of an I/O APIC input is > certainly beyond the ACPI spec), hide its documentation and still > demand it to be supported correctly, possibly hurting all the other > good equipment. Sorry -- you have to draw a line somewhere. [...] agreed. This is a clear example of a complex and hard to track down BIOS bug - and even in this case we go out on a limb working it around. The first approach to such problems is usually a DMI pattern based fix - they happen when we dont know the full scope of a particular problem yet but have a rough idea and want to react to bugs quickly. PCI ID based quirks are preferred much more in the long run: DMI pattern matching does not scale as the DMI space is human-visible and hence changes frequently not for technical/hw-environment but for perception/PR reasons, hence it is far less reliable programmatically than the PCI ID space. But PCI ID methods, while more intelligent, they lag behind a bit and depend on good cooperation with hw makers. As long as DMI pattern matches end up turning into PCI ID based approaches, like here, i'm not complaining as a maintainer ;) Thanks Maciej for your excellent in-depth analysis of this issue, and for your many fixes in this area of code - you squashed many difficult, long-standing bugs in this space. Ingo -- 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/