From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754964AbZBWVMY (ORCPT ); Mon, 23 Feb 2009 16:12:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751875AbZBWVMO (ORCPT ); Mon, 23 Feb 2009 16:12:14 -0500 Received: from cantor.suse.de ([195.135.220.2]:41315 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750973AbZBWVMN (ORCPT ); Mon, 23 Feb 2009 16:12:13 -0500 From: Thomas Renninger To: alan-jenkins@tuffmail.co.uk, Kay Sievers Subject: Re: [PATCH] cpufreq: Change link order of x86 cpufreq modules Date: Mon, 23 Feb 2009 22:12:23 +0100 User-Agent: KMail/1.9.10 Cc: Ingo Molnar , Matthew Garrett , davej@codemonkey.org.uk, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org References: <20090218182822.GA19902@srcf.ucam.org> <20090218190943.GF26802@elte.hu> <9b2b86520902190354m259f85d0n97795da7b1b8afdd@mail.gmail.com> In-Reply-To: <9b2b86520902190354m259f85d0n97795da7b1b8afdd@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200902232212.23925.trenn@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 19 February 2009 12:54:06 pm Alan Jenkins wrote: > On 2/18/09, Ingo Molnar wrote: > > * Matthew Garrett wrote: > >> On Wed, Feb 18, 2009 at 07:31:37PM +0100, Ingo Molnar wrote: > >> > Nice fix! Where does this information come from? Distro module > >> > ordering magic? It's rather non-trivial. > >> > >> Pretty much. p4-clockmod is never the preferred option because > >> it does no voltage scaling. speedstep-centrino is now almost > >> entirely functionally replaced with acpi-cpufreq. The > >> powernow-k8 issue was a personal communication from davej. > > > > I'm wondering whether that priority order should/could be > > expressed in the module space too - so that distros wouldnt have > > to replicate this. This is really a piece of information the > > kernel is best at maintaining. > > The latest development version of module-init-tools (in the git tree) > is designed to preserve the kernel link order when resolving builtin > aliases. If you have two modules which provide the alias "pci:123", > they will be loaded in the same order as if they were builtin drivers. > > It should work if all the cpufreq drivers provide an alias > "cpufreq-driver" and userspace just does "modprobe cpufreq-driver". > You just need to be sure none of the cpufreq drivers provide *other* > aliases which cause them to be loaded earlier, by udev or some other > bootscript. I wonder whether a "cpu:vendor:fam:model:flags:..." alias makes sense. This would solve autoloading of most cpufreq drivers, but it never looked important enough. Other drivers that could make use of this: - k8temp/k10temp (Don't know about this one, but AFAIK there exists an MSR to read out temperature on latest AMD for which a hwmon driver is/should be written)? - Microcode update? - more? Thomas