From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754889Ab0CQOtT (ORCPT ); Wed, 17 Mar 2010 10:49:19 -0400 Received: from mail-bw0-f212.google.com ([209.85.218.212]:36974 "EHLO mail-bw0-f212.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750698Ab0CQOtQ (ORCPT ); Wed, 17 Mar 2010 10:49:16 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=rloOdYM4trLsAkCNe7+kw2xvyyO4u/aZeD3bJygr38PPsqgu+kbE7SRPc7c0MxRWeo MUfDn0E3Q4Djq9o7Eh4J0atd3VitBgARKFu7VSa5/RCujQg0mb9VH21j71mW+4DINifJ uHtyI2LVl3fOpKwN7Jl4Vxm973oKlMsVQqSmk= MIME-Version: 1.0 In-Reply-To: References: <71cd59b01003120049n1a9fbbf3qfd37f14f241a7f64@mail.gmail.com> <71cd59b01003130116h4265769v9e1dae95361629ce@mail.gmail.com> Date: Wed, 17 Mar 2010 14:49:13 +0000 Message-ID: <9b2b86521003170749t5008c5cbpc2064988b59f1507@mail.gmail.com> Subject: Re: Possible bug in eeepc-laptop.c - EeePC 900 From: Alan Jenkins To: Fabio Comolli Cc: Corentin Chary , ACPI mailing list , Linux Kernel Mailing List , Len Brown Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > 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. Alan