Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756677AbcCXOR3 (ORCPT ); Thu, 24 Mar 2016 10:17:29 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:36172 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbcCXORW (ORCPT ); Thu, 24 Mar 2016 10:17:22 -0400 MIME-Version: 1.0 Reply-To: cw00.choi@samsung.com In-Reply-To: <56F3F11E.9090200@math.uni-bielefeld.de> References: <1458793530-31897-1-git-send-email-cw00.choi@samsung.com> <56F36D65.6030504@samsung.com> <56F3EE8E.3020308@fivetechno.de> <56F3F11E.9090200@math.uni-bielefeld.de> Date: Thu, 24 Mar 2016 23:17:20 +0900 Message-ID: Subject: Re: [PATCH v5 00/21] PM / devferq: Add generic exynos bus frequency driver and new passive governor From: Chanwoo Choi To: Tobias Jakobi Cc: Markus Reichl , "myungjoo.ham@samsung.com" , Kyungmin Park , =?UTF-8?Q?Krzysztof_Koz=C5=82owski?= , Kukjin Kim , Anand Moon , "Rafael J. Wysocki" , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King - ARM Linux , linux-kernel , "linux-pm@vger.kernel.org" , linux-samsung-soc , linux-arm-kernel , devicetree Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2055 Lines: 61 Hi Tobias, On Thu, Mar 24, 2016 at 10:52 PM, Tobias Jakobi wrote: > Hello everybody, > > > Markus Reichl wrote: >> Hi Chanwoo, >> >> Am 24.03.2016 um 05:30 schrieb Chanwoo Choi: >>> Dear Anand and Tobias, >>> >>> To Anand, >>> First of all, thanks to your test on previous patchset. >>> I removed the your tested-by tag from this version >>> because I modified the devfreq core using DEVFREQ_TRANSITION_NOTIFIER notifier. >>> I think that this patch-set need to test with this patchset. >>> If you possible, could you please test this patch-set? Thanks in advance. >>> >>> To Tobias, >>> I fixed the following issues reported by you. Thanks your test and report. >>> - RCU locking issue >>> - debugfs error during kernel booting >>> >>> Best Regards, >>> Chanwoo Choi >> >> This set works fine on odroid U3 but gives the following with dmesg |grep devfreq: >> >> [ 2.066890] devfreq bus_dmc: Couldn't update frequency transition information. >> [ 2.190238] devfreq bus_leftbus: Couldn't update frequency transition information. > I have yet to test this new iteration of the patchset, but this message > looks familiar. I already encountered it with the older version applied > to vanilla-4.5.y. > > The messages happen when devfreq_update_status() (in > drivers/devfreq/devfreq.c) encounters a uninitialized (zero) > previous_freq. I have currently fixed this in my local tree by just > skipping (goto out) devfreq_update_status() in that case. I agree. Your comment is correct. > > Maybe it would be more elegant to set previous_freq to something sane on > probe. IIRC then it is set from initial_freq on probe, but the exynos > code doesn't set this one. The devfreq have already this issue before sending my patches. So, I think that you better to send your fixup patch. Maybe, the exynos-bus.c read the current frequency in the probe function and then devfreq core should set the devfreq->previous_freq field. > > Maybe this info is helpful? Your info is very helpful. Thanks. Best Regards, Chanwoo Choi