From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: Disabling power management firmware decisions Date: Thu, 19 Mar 2015 16:34:52 +0100 Message-ID: <550AEC9C.5030308@linaro.org> References: <550AD02E.2080507@linaro.org> <4773622.DqM2RS9PPh@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-wi0-f180.google.com ([209.85.212.180]:38351 "EHLO mail-wi0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbbCSPe4 (ORCPT ); Thu, 19 Mar 2015 11:34:56 -0400 Received: by wifj2 with SMTP id j2so72565128wif.1 for ; Thu, 19 Mar 2015 08:34:55 -0700 (PDT) In-Reply-To: <4773622.DqM2RS9PPh@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Len Brown , Linux PM mailing list On 03/19/2015 03:08 PM, Rafael J. Wysocki wrote: > On Thursday, March 19, 2015 02:33:34 PM Daniel Lezcano wrote: >> >> Hi, >> >> I would like to do some experiments with the x86 platform but I am >> facing one big issue. >> >> When I use the rapl register to measure the energy consumption with >> turbostat and another tool written by me. I see no differences betwe= en >> my kernel changes while using the idlestat tool, I see big differenc= es >> in the idle state durations with the traces. >> >> I remember on x86 the firmware overrides all kernel decisions to do = the >> power management. So I assume, it is possible my changes are not >> measurable because of that. >> >> Is there a way to tell the firmware to stop overriding the kernel >> decisions in order to let the kernel handle idle/dvfs on its own ? > > The short answer to that is no, there isn't. It also may not be firm= ware, > but hardware. mmrfh, that's not funny :( Thanks for the answer. -- Daniel --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog