From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757543AbZBSMEU (ORCPT ); Thu, 19 Feb 2009 07:04:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753642AbZBSMEK (ORCPT ); Thu, 19 Feb 2009 07:04:10 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:49117 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753038AbZBSMEJ (ORCPT ); Thu, 19 Feb 2009 07:04:09 -0500 Date: Thu, 19 Feb 2009 13:03:52 +0100 From: Ingo Molnar To: alan-jenkins@tuffmail.co.uk Cc: Matthew Garrett , davej@codemonkey.org.uk, linux-kernel@vger.kernel.org, cpufreq@vger.kernel.org Subject: Re: [PATCH] cpufreq: Change link order of x86 cpufreq modules Message-ID: <20090219120352.GA1703@elte.hu> References: <20090218182822.GA19902@srcf.ucam.org> <20090218183137.GD26802@elte.hu> <20090218183641.GA20203@srcf.ucam.org> <20090218190943.GF26802@elte.hu> <9b2b86520902190354m259f85d0n97795da7b1b8afdd@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9b2b86520902190354m259f85d0n97795da7b1b8afdd@mail.gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * 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. very nifty ... > 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. yeah. Nice. Ingo