From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751827AbaEBIrs (ORCPT ); Fri, 2 May 2014 04:47:48 -0400 Received: from mail-wi0-f173.google.com ([209.85.212.173]:51045 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751386AbaEBIrq (ORCPT ); Fri, 2 May 2014 04:47:46 -0400 Message-ID: <53635BB4.30900@linaro.org> Date: Fri, 02 May 2014 10:47:48 +0200 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Linux PM list , Linux Kernel Mailing List , Ingo Molnar , Peter Zijlstra Subject: Re: [PATCH 2/2] cpuidle / menu: Return error code if there are no suitable states References: <2471963.urOyfY8mOG@vostro.rjw.lan> <535E3818.2040905@linaro.org> <2000825.kO1es8ShkW@vostro.rjw.lan> <1516317.nEvPfS8aZ7@vostro.rjw.lan> In-Reply-To: <1516317.nEvPfS8aZ7@vostro.rjw.lan> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/30/2014 01:16 AM, Rafael J. Wysocki wrote: > On Tuesday, April 29, 2014 01:28:03 AM Rafael J. Wysocki wrote: >> On Monday, April 28, 2014 01:14:32 PM Daniel Lezcano wrote: >>> On 04/27/2014 02:55 PM, Rafael J. Wysocki wrote: [ ... ] > --- > From: Rafael J. Wysocki > Subject: cpuidle / menu: Return (-1) if there are no suitable states > > If there is a PM QoS latency limit and all of the sufficiently shallow > C-states are disabled, the cpuidle menu governor returns 0 which on > some systems is CPUIDLE_DRIVER_STATE_START and shouldn't be returned > if that C-state has been disabled. > > Fix the issue by modifying the menu governor to return (-1) in such > situations. > > Signed-off-by: Rafael J. Wysocki > --- > drivers/cpuidle/governors/menu.c | 2 +- > include/linux/cpuidle.h | 2 ++ > 2 files changed, 3 insertions(+), 1 deletion(-) > > Index: linux-pm/drivers/cpuidle/governors/menu.c > =================================================================== > --- linux-pm.orig/drivers/cpuidle/governors/menu.c > +++ linux-pm/drivers/cpuidle/governors/menu.c > @@ -296,7 +296,7 @@ static int menu_select(struct cpuidle_dr > data->needs_update = 0; > } > > - data->last_state_idx = 0; > + data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1; In case of x86, CPUIDLE_DRIVER_STATE_START will be 1, so the select function could return 0 even this one is disabled and this is not what you want to happen, no ? > /* Special case when user has set very strict latency requirement */ > if (unlikely(latency_req == 0)) > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog