Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932981AbbGUP35 (ORCPT ); Tue, 21 Jul 2015 11:29:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33300 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932933AbbGUP3z (ORCPT ); Tue, 21 Jul 2015 11:29:55 -0400 Date: Tue, 21 Jul 2015 08:29:54 -0700 From: Greg KH To: Mason Cc: stable@vger.kernel.org, LKML , Lukasz Majewski , Zhang Rui Subject: Re: Requesting inclusion of 26bb0e9a in linux-3.14.y Message-ID: <20150721152954.GC2833@kroah.com> References: <55AE2FD5.3000207@free.fr> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55AE2FD5.3000207@free.fr> User-Agent: Mutt/1.5.23+102 (2ca89bed6448) (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3257 Lines: 80 On Tue, Jul 21, 2015 at 01:41:09PM +0200, Mason wrote: > Hello, > > This is my first time requesting inclusion of a patch, please > point out any breach of protocol. > > I'm using linux-3.14.y and I've run into a bug fixed in later > kernel versions: > > commit 26bb0e9a1a938ec98ee07aa76533f1a711fba706 > Author: Lukasz Majewski > Date: Wed Sep 24 10:27:10 2014 +0200 > > thermal: step_wise: fix: Prevent from binary overflow when trend is dropping > > 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 > Signed-off-by: Zhang Rui > > diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c > index f251521baaa2..6705a0d746b3 100644 > --- a/drivers/thermal/step_wise.c > +++ b/drivers/thermal/step_wise.c > @@ -76,7 +76,7 @@ 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 { > > > > > Here's the debug output on my board: > > [ 21.301211] thermal thermal_zone0: last_temperature=0, current_temperature=51000 > [ 21.308803] thermal thermal_zone0: Trip0[type=1,temp=70000]:trend=1,throttle=0 > [ 21.316248] thermal cooling_device0: cur_state=0 > [ 21.320957] thermal cooling_device0: old_target=-1, target=-1 > [ 21.326755] thermal cooling_device0: zone0->target=4294967295 > [ 21.332544] thermal cooling_device0: set to state 0 > > [ 34.349747] thermal thermal_zone0: last_temperature=51000, current_temperature=46000 > [ 34.357830] thermal thermal_zone0: Trip0[type=1,temp=70000]:trend=2,throttle=0 > [ 34.365254] thermal cooling_device0: cur_state=0 > [ 34.369989] thermal cooling_device0: old_target=-1, target=4 > [ 34.375740] thermal cooling_device0: zone0->target=4 > [ 34.380867] thermal cooling_device0: set to state 4 > > Bug: raising the cooling state, despite the temperature dropping. > > The .bind() call was > > thermal_zone_bind_cooling_device(tz, 0, cdev, 4, 1); > > (The intent being that, once the system is above the trip temp, > at least a little bit of cooling should be applied, always.) > > cur_state = 0 is not equal to lower_state = 1 > > AFAICT, Lukasz's patch fixes that issue. Now queued up, thanks. greg k-h -- 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/