From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: [PATCH 1/3] thermal: step_wise: fix: Prevent from binary overflow when trend is dropping Date: Thu, 09 Oct 2014 11:14:18 +0800 Message-ID: <1412824458.13621.5.camel@rzhang1-toshiba> References: <1411547232-21493-1-git-send-email-l.majewski@samsung.com> <1411547232-21493-2-git-send-email-l.majewski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com ([192.55.52.88]:63299 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751125AbaJIDOW (ORCPT ); Wed, 8 Oct 2014 23:14:22 -0400 In-Reply-To: <1411547232-21493-2-git-send-email-l.majewski@samsung.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Lukasz Majewski Cc: Eduardo Valentin , Linux PM list , Lukasz Majewski , Bartlomiej Zolnierkiewicz , linux-kernel@vger.kernel.org On Wed, 2014-09-24 at 10:27 +0200, Lukasz Majewski wrote: > It turns out that some boards can have instance->lower greater than 0 and > when thermal trend is dropping it results with next_target equal to -1. > > Since the next_target is defined as unsigned long it is interpreted as > 0xFFFFFFFF and larger than instance->upper. > As a result the next_target is set to instance->upper which ramps up to > maximal cooling device target when the temperature is steadily decreasing. > > Signed-off-by: Lukasz Majewski applied. thanks, rui > --- > drivers/thermal/step_wise.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c > index 3b54c2c..fdd1f52 100644 > --- a/drivers/thermal/step_wise.c > +++ b/drivers/thermal/step_wise.c > @@ -77,7 +77,7 @@ static unsigned long get_target_state(struct thermal_instance *instance, > next_target = instance->upper; > break; > case THERMAL_TREND_DROPPING: > - if (cur_state == instance->lower) { > + if (cur_state <= instance->lower) { > if (!throttle) > next_target = THERMAL_NO_TARGET; > } else {