From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756122AbXKXW0S (ORCPT ); Sat, 24 Nov 2007 17:26:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752662AbXKXW0J (ORCPT ); Sat, 24 Nov 2007 17:26:09 -0500 Received: from gate.crashing.org ([63.228.1.57]:46670 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752613AbXKXW0I (ORCPT ); Sat, 24 Nov 2007 17:26:08 -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: <20071124232035.0f46d530@hyperion.delvare> References: <1195427766.7022.18.camel@pasglop> <200711231700.53103.mb@bu3sch.de> <20071123232928.467378a7@hyperion.delvare> <200711241518.26755.mb@bu3sch.de> <20071124232035.0f46d530@hyperion.delvare> Content-Type: text/plain Date: Sun, 25 Nov 2007 09:25:35 +1100 Message-Id: <1195943135.7195.61.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 > Very strange indeed. Another possibility is that there is a hardware > monitoring chip connected to one of the Radeon adapter's I2C buses, and > that holding the I2C lines prevents reading from it, so whatever is > responsible for controlling the temperature prefers to play it safe and > shuts everything down. Somehow it seems more realistic than an actual > overheating (3 seconds is a very short period of time for that), but > we'd need the exact schematics of the hardware, and the details of the > thermal control system, to validate this theory. > > Anyway, no need to worry anymore now that the bug is fixed :) Actually, that's a possibility yes, though generally Apple put all temp. monitoring chips elsewhere, it could well be the case. Ben.