Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751367AbWJ1Tx7 (ORCPT ); Sat, 28 Oct 2006 15:53:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751370AbWJ1Tx7 (ORCPT ); Sat, 28 Oct 2006 15:53:59 -0400 Received: from mx1.redhat.com ([66.187.233.31]:1711 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1751367AbWJ1Tx6 (ORCPT ); Sat, 28 Oct 2006 15:53:58 -0400 Date: Sat, 28 Oct 2006 15:53:49 -0400 From: Dave Jones To: Ben Collins Cc: Linux Kernel , Pallipadi@pressure.kernelslacker.org, Venkatesh Subject: p4-clockmod N60 errata workaround. Message-ID: <20061028195349.GH27101@redhat.com> Mail-Followup-To: Dave Jones , Ben Collins , Linux Kernel , Pallipadi, Venkatesh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1516 Lines: 36 Ben, For the best part of a year since that N60 errata workaround went in, I've had floods of complaints from users of that driver about this driver becoming even more useless than it was before "I had 8 frequencies, now I have 2" being the common complaint. which was to be expected given that the intention of the errata workaround was to cripple frequencies <2GHz. The point worth noting however, is that none of these users ever noticed any problems when we didn't have the workaround in place, so they were somewhat miffed when it stopped working. The actual errata states.. "If a system de-asserts STPCLK# at a 12.5% duty cycle, the processor is running below 2 GHz, and the processor thermal control circuit (TCC) on-demand clock modulation is active, the processor may hang. This erratum does not occur under the automatic mode of the TCC." I believe the reason we never saw any problems is that we _are_ using the TCC by default. See the code in arch/i386/kernel/cpu/mcheck/p4.c intel_init_thermal() and friends. So my current feeling is that we're working around an errata that can never happen, and crippling functionality in the process for no good reason. I'm leaning towards just removing this workaround. Dave -- http://www.codemonkey.org.uk - 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/