From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753687AbXKXBLg (ORCPT ); Fri, 23 Nov 2007 20:11:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752587AbXKXBL2 (ORCPT ); Fri, 23 Nov 2007 20:11:28 -0500 Received: from gate.crashing.org ([63.228.1.57]:43227 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752544AbXKXBL2 (ORCPT ); Fri, 23 Nov 2007 20:11:28 -0500 Subject: Re: radeonfb i2c regression post-2.6.18. From: Benjamin Herrenschmidt Reply-To: benh@kernel.crashing.org To: Jean Delvare Cc: Michael Buesch , Roger Leigh , linux-kernel@vger.kernel.org, Dennis Munsie In-Reply-To: <20071123232928.467378a7@hyperion.delvare> References: <1195427766.7022.18.camel@pasglop> <200711231700.53103.mb@bu3sch.de> <20071123232928.467378a7@hyperion.delvare> Content-Type: text/plain Date: Sat, 24 Nov 2007 12:11:04 +1100 Message-Id: <1195866664.7195.28.camel@pasglop> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2007-11-23 at 23:29 +0100, Jean Delvare wrote: > On Fri, 23 Nov 2007 17:00:52 +0100, Michael Buesch wrote: > > This patch fixes my crash problem. > > Out of curiosity, what kind of crash was it? I admit that I can't see > how the code could crash. Really sneaky... apparently, keeping the i2c lines asserted on his laptop model would drain enough current through the pullups (or the chip) that the temperature will raise significantly, causing a thermal shutdown if the machine was already warm. A bit scary... looks to me that a pullup is a bit too weak somewhere on the motherboard. That also means that this fix should reduce power consumption on the battery significantly on those machines as it must take quite a bit of power to increase the temperature that significantly (either that, or the heating part sits just next to the sensor). Cheers, Ben.