Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754851AbaJIDP3 (ORCPT ); Wed, 8 Oct 2014 23:15:29 -0400 Received: from mga09.intel.com ([134.134.136.24]:39153 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753574AbaJIDPV (ORCPT ); Wed, 8 Oct 2014 23:15:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,682,1406617200"; d="scan'208";a="615559258" Message-ID: <1412824517.13621.6.camel@rzhang1-toshiba> Subject: Re: [PATCH 3/3] thermal: core: fix: Check return code of the ->get_max_state() callback From: Zhang Rui To: Lukasz Majewski Cc: Eduardo Valentin , Linux PM list , Lukasz Majewski , Bartlomiej Zolnierkiewicz , linux-kernel@vger.kernel.org Date: Thu, 09 Oct 2014 11:15:17 +0800 In-Reply-To: <20141003124054.404ac26c@amdc2363> References: <1411547232-21493-1-git-send-email-l.majewski@samsung.com> <1411547232-21493-4-git-send-email-l.majewski@samsung.com> <20141002222441.GA11510@developer> <20141003124054.404ac26c@amdc2363> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.8.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2014-10-03 at 12:40 +0200, Lukasz Majewski wrote: > Hi Eduardo, Rui, > > > On Wed, Sep 24, 2014 at 10:27:12AM +0200, Lukasz Majewski wrote: > > > Without this check it was possible to execute cooling device > > > binding code even when wrong max cooling state was read. > > > > > > Signed-off-by: Lukasz Majewski > > > > Acked-by: Eduardo Valentin > > > > Rui, are you taking these patches? Do you prefer me to collect them? > > I'd like to ask you NOT to apply those patches. > > In short: It will cause regression on all non Exynos boards. > > Explanation: > > Up till now the cpu_cooling device was bind even when the > get_max_state() returned -EINVAL and everything worked after late > cpufreq policy initialization. > > However, during this time window the thermal driver is not properly > configured. > > Applying PATCH2/3 and PATCH3/3 would cause bind error without any > further occasion for re-bind. As a result THERAL will not be present > on the target system. > > It works on the Exynos boards, since at the report_trigger() function, > when first trip point is reached, it is checked if cpu_cooling device > is bind. If it is not (due to "fixes" at PATCH2/3 and PATCH3/3) it > is rebind then. > > Due to above, I think that it would be best to leave things as they are > now and prepare proper fix as suggested by Eduardo. > Agreed. Can anyone please propose such a patch? thanks, rui > > > > Cheers > > > > Eduardo > > > > > --- > > > drivers/thermal/thermal_core.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/thermal/thermal_core.c > > > b/drivers/thermal/thermal_core.c index 747618a..8a4dc35 100644 > > > --- a/drivers/thermal/thermal_core.c > > > +++ b/drivers/thermal/thermal_core.c > > > @@ -928,7 +928,7 @@ int thermal_zone_bind_cooling_device(struct > > > thermal_zone_device *tz, struct thermal_zone_device *pos1; > > > struct thermal_cooling_device *pos2; > > > unsigned long max_state = 0; > > > - int result; > > > + int result, ret; > > > > > > if (trip >= tz->trips || (trip < 0 && trip != > > > THERMAL_TRIPS_NONE)) return -EINVAL; > > > @@ -945,7 +945,9 @@ int thermal_zone_bind_cooling_device(struct > > > thermal_zone_device *tz, if (tz != pos1 || cdev != pos2) > > > return -EINVAL; > > > > > > - cdev->ops->get_max_state(cdev, &max_state); > > > + ret = cdev->ops->get_max_state(cdev, &max_state); > > > + if (ret) > > > + return ret; > > > > > > /* lower default 0, upper default max_state */ > > > lower = lower == THERMAL_NO_LIMIT ? 0 : lower; > > > -- > > > 2.0.0.rc2 > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/