Hi Peter, On Tue, Apr 29, 2014 at 10:31:42PM +0100, Peter Feuerer wrote: > 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 <[email protected]> > >>> + * > >>> + * Based on step_wise.c with following Copyrights: > >>> + * Copyright (C) 2012 Intel Corp > >>> + * Copyright (C) 2012 Durgadoss R <[email protected]> > >>> + * > >>> + * > >>> + * 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 <linux/thermal.h> > >>> + > >>> +#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; > + }
That sounds like a better solution, thanks! Javi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
