Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762031AbXEQVwR (ORCPT ); Thu, 17 May 2007 17:52:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755889AbXEQVwH (ORCPT ); Thu, 17 May 2007 17:52:07 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:39251 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755961AbXEQVwF (ORCPT ); Thu, 17 May 2007 17:52:05 -0400 Date: Thu, 17 May 2007 23:52:03 +0200 From: Pavel Machek To: Len Brown Cc: Chuck Ebbert , len.brown@intel.com, Maciej Rutecki , Andrew Morton , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, torvalds@linux-foundation.org Subject: Re: 2.6.22-rc1-mm1 [cannot change thermal trip points] Message-ID: <20070517215203.GB7336@elf.ucw.cz> References: <20070515201914.16944e04.akpm@linux-foundation.org> <464B43BB.3070505@redhat.com> <20070517092318.GD3975@ucw.cz> <200705171517.14087.lenb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200705171517.14087.lenb@kernel.org> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1799 Lines: 46 Hi! > > > ACPI: thermal trip points are read-only > > > > What was the rationale? Can we get this one reverted? > > > > Some machines (HP omnibook xe3) have broken trip points -- too high -- > > so machine will overheat and trigger hw shutdown before starting > > passive cooling. > > > > That's really broken, and write to trip points is reasonable way to > > 'fix' that. (I'd understand if you only ever let trip points to > > decrease... but otoh root should be able to shoot himself....) > > No, writing trip-points is neither a fix, nor it is reasonable. > It is a workaround at best, and it is a dangerous and mis-leading hack. > > The OS has no capability to actually change the ACPI trip points > that are used by the BIOS. Changing the OS copy of them > to make the user think that trip events will actually > happen when the temperature crosses the OS copy is crazy. Aha... wait. It seemed to work for me when I enabled thermal polling... Slowing cpu down / shutdown / turn the fan on is done in the os after all. Should we just start polling temperatures when user writes custom trip points? > If there are systems with broken thermals and the > ACPI thermal control needs and over-ride to turn > on the fan, then that is fine -- but using > fake trip-points and giving the user the impression > that they are real is not viable. They become real when we fake _TSP, too, ..? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/