From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752808Ab0CQPqx (ORCPT ); Wed, 17 Mar 2010 11:46:53 -0400 Received: from mail-ew0-f209.google.com ([209.85.219.209]:53891 "EHLO mail-ew0-f209.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751566Ab0CQPqu convert rfc822-to-8bit (ORCPT ); Wed, 17 Mar 2010 11:46:50 -0400 X-Greylist: delayed 384 seconds by postgrey-1.27 at vger.kernel.org; Wed, 17 Mar 2010 11:46:50 EDT DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=rvCRfvD4sWz6CwGwe2WpZPuAu4krZYCWv1wPqGBZl+HDgVk7lpTcE1nqqSM3btXHVv vZmedCZTNVcy9qgvKgXED7eIqK4VOXctyXwSYeGOhmshV+MicUl1sGqRoEeVj8yIT6vO rI9g5wRUELS+MosP22VSegDqVObhRPISE6BvQ= MIME-Version: 1.0 In-Reply-To: <9b2b86521003170749t5008c5cbpc2064988b59f1507@mail.gmail.com> References: <71cd59b01003120049n1a9fbbf3qfd37f14f241a7f64@mail.gmail.com> <71cd59b01003130116h4265769v9e1dae95361629ce@mail.gmail.com> <9b2b86521003170749t5008c5cbpc2064988b59f1507@mail.gmail.com> Date: Wed, 17 Mar 2010 16:40:24 +0100 Message-ID: Subject: Re: Possible bug in eeepc-laptop.c - EeePC 900 From: Fabio Comolli To: Alan Jenkins Cc: Corentin Chary , ACPI mailing list , Linux Kernel Mailing List , Len Brown Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi On Wed, Mar 17, 2010 at 3:49 PM, Alan Jenkins wrote: > On 3/13/10, Fabio Comolli wrote: >> Well, I'm confused. >> >> I rebooted with the "vanilla" eeepc-laptop.c and I'm sorry to say that >> the situation it's not like the one I described in the post I wrote 2 >> days ago. Actually the situation with the patch reverted is the same I >> have with the patch applied. >> >> What I mean is that if I boot on AC power /proc/cpuinfo always reports >> 900MHz and 1800 bogomips. It I boot on battery /proc/cpuinfo always >> reports 630MHz and 1260 bogomips. Plugging / unplugging the AC does >> not change the situation. Only reboot does. >> >> But the cpufv interface does indeed seem to work, as glxgears and >> stellarium show the frame rate change accordingly to the powersave / >> performance selection. >> >> So my question is: what does really the cpufv interface do? Is it >> supposed to change the processor frequency? > > Yes, writing to cpufv asks the BIOS to set the CPU speed. OK > >> And if the answer to the latest question is affirmative, why >> /proc/cpuinfo seems to ignore it? > > It's because eeepc-laptop doesn't register as a real cpufreq driver. > The BIOS doesn't tell us what frequency it switches to.  Theoretically > you could re-use the boot code, but I'm not sure how you would make it > co-operate with the cpufreq core. OK, now I understand. Thanks. So it seems that the only way to get the actual CPU frequency is to query the cpufv sysfs file. Good to know. Unless someone with the required knowledge comes up with the code needed to register eeepc-laptop as a real cpufreq driver (hint, hint :-) ) > > Alan > Thanks, Fabio