Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964792AbVJDItN (ORCPT ); Tue, 4 Oct 2005 04:49:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964795AbVJDItN (ORCPT ); Tue, 4 Oct 2005 04:49:13 -0400 Received: from vulpecula.futurs.inria.fr ([195.83.212.5]:64916 "EHLO vulpecula.futurs.inria.fr") by vger.kernel.org with ESMTP id S964792AbVJDItM (ORCPT ); Tue, 4 Oct 2005 04:49:12 -0400 Message-ID: <43424202.7070600@lifl.fr> Date: Tue, 04 Oct 2005 10:49:06 +0200 From: Eric Piel User-Agent: Mozilla Thunderbird 1.0.6-7mdk (X11/20050322) X-Accept-Language: fr, en MIME-Version: 1.0 To: Benjamin Herrenschmidt Cc: Andrew Morton , Linux Kernel list , linuxppc64-dev Subject: Re: [PATCH] ppc64: Add cpufreq support for SMU based G5 References: <1128403842.31063.24.camel@gaston> In-Reply-To: <1128403842.31063.24.camel@gaston> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1752 Lines: 38 10/04/2005 07:30 AM, Benjamin Herrenschmidt wrote/a écrit: > iMac G5 and latest single CPU desktop G5 (SMU based machines) have a > 970FX DD3 CPU that supports frequency & vooltage switching. This patch > adds support for simple dual frequency switch. It is required for the > upcoming thermal control patch for these machines. > Hello, I know only very little about cpufreq, probably you could post your patch to the cpufreq mailing list for better review : cpufreq@lists.linux.org.uk (you may have to subscride before posting, don't remember). For what have seen, your patch looks pretty good in general. However, is this kind of CPU only in one CPU machines? Your patch doesn't seem support SMP, then it's probably safer to prevent compilation on an SMP kernel in the Makefile? Or you can add SMP support (shouldn't be so hard in theory, but with no hardware to test it might be pointless), you can have a look at other drivers that support it, like in arch/i386/kernel/cpu/cpufreq/p4-clockmod.c . Just a little more thing, concerning: + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; Could you have a look if you could find the real info about how long it takes to change the speed (put the worse case latency)? Maybe the info can be found in some parts of the ROM you read? I don't know if conservative or ondemand governors are supposed to be able to mix with your code (especially wrt Windfarm) but not putting this info will prevent them from ever working... Cheers, Eric - 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/