Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932116AbaD2Vbr (ORCPT ); Tue, 29 Apr 2014 17:31:47 -0400 Received: from smtprelay02.ispgateway.de ([80.67.31.25]:52147 "EHLO smtprelay02.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757271AbaD2Vbq (ORCPT ); Tue, 29 Apr 2014 17:31:46 -0400 References: <1398561815-22033-1-git-send-email-peter@piie.net> <1398763077-5542-1-git-send-email-peter@piie.net> <1398763077-5542-4-git-send-email-peter@piie.net> <20140429155323.GB31488@e102654-lin.cambridge.arm.com> Message-ID: X-Mailer: http://www.courier-mta.org/cone/ From: Peter Feuerer To: Peter Feuerer Cc: Javi Merino , LKML , Zhang Rui , Andreas Mohr , Borislav Petkov Subject: Re: [PATCH v2 3/4] thermal: Added Bang-bang thermal governor Date: Tue, 29 Apr 2014 23:31:42 +0200 Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Df-Sender: NDA0MDk0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Javi, Peter Feuerer writes: > Javi Merino writes: [...] >>> diff --git a/drivers/thermal/gov_bang_bang.c b/drivers/thermal/gov_bang_bang.c >>> new file mode 100644 >>> index 0000000..328dde0 >>> --- /dev/null >>> +++ b/drivers/thermal/gov_bang_bang.c >>> @@ -0,0 +1,124 @@ >>> +/* >>> + * gov_bang_bang.c - A simple thermal throttling governor using hysteresis >>> + * >>> + * Copyright (C) 2014 Peter Feuerer >>> + * >>> + * Based on step_wise.c with following Copyrights: >>> + * Copyright (C) 2012 Intel Corp >>> + * Copyright (C) 2012 Durgadoss R >>> + * >>> + * >>> + * This program is free software; you can redistribute it and/or modify >>> + * it under the terms of the GNU General Public License as published by >>> + * the Free Software Foundation, version 2. >>> + * >>> + * This program is distributed in the hope that it will be useful, >>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See >>> + * the GNU General Public License for more details. >>> + * >>> + */ >>> + >>> +#include >>> + >>> +#include "thermal_core.h" >>> + >>> +static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) >>> +{ >>> + long trip_temp; >>> + unsigned long trip_hyst; >>> + struct thermal_instance *instance; >>> + >>> + tz->ops->get_trip_temp(tz, trip, &trip_temp); >>> + tz->ops->get_trip_hyst(tz, trip, &trip_hyst); >>> + >>> + dev_dbg(&tz->device, "Trip%d[temp=%ld]:temp=%d:hyst=%ld\n", >>> + trip, trip_temp, tz->temperature, >>> + trip_hyst); >>> + >>> + mutex_lock(&tz->lock); >>> + >>> + list_for_each_entry(instance, &tz->thermal_instances, tz_node) { >>> + if (instance->trip != trip) >>> + continue; >>> + >>> + /* in case fan is neither on nor off set the fan to active */ >>> + if (instance->target != 0 && instance->target != 1) >>> + instance->target = 1; >> >> I think you should add a pr_warn() here to warn the user that the >> governor is being used with a cooling device that seems to support >> more than one cooling state. > > Strange thing is, that the first time it is actually called with acerhdf > attached, it comes in with instance→target = -1 … I did not yet find out, > why. > > I'll further investigate on this and add some warning to it. I found out, that the default init state of a cooling device is: drivers/thermal/thermal_core.c: 960 dev->target = THERMAL_NO_TARGET; While drivers/thermal/thermal_core.h: 30 /* Initial state of a cooling device during binding */ 31 #define THERMAL_NO_TARGET -1UL So I changed my patch to this: + /* in case fan is in initial state, switch the fan off */ + if (instance->target == THERMAL_NO_TARGET) + instance->target = 0; + + /* in case fan is neither on nor off set the fan to active */ + if (instance->target != 0 && instance->target != 1) { + pr_warn("Thermal instance %s controlled by bang-bang has unexpected state: %ld\n", + instance->name, instance->target); + instance->target = 1; + } -- kind regards, --peter; -- 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/