On 15/12/2020 00:38, Daniel Lezcano wrote: > The code was reorganized in 2012 with the commit 0c01ebbfd3caf1. > > The main change is a loop on the trip points array and a unconditional > call to the throttle() ops of the governors for each of them even if > the trip temperature is not reached yet. > > With this change, the 'forced_passive' is no longer checked in the > thermal_zone_device_update() function but in the step wise governor's > throttle() callback. > > As the force_passive does no belong to the trip point array, the > thermal_zone_device_update() can not compare with the specified > passive temperature, thus does not detect the passive limit has been > crossed. Consequently, throttle() is never called and the > 'forced_passive' branch is unreached. > > In addition, the default processor cooling device is not automatically > bound to the thermal zone if there is not passive trip point, thus the > 'forced_passive' can not operate. > > If there is an active trip point, then the throttle function will be > called to mitigate at this temperature and the 'forced_passive' will > override the mitigation of the active trip point in this case but with > the default cooling device bound to the thermal zone, so usually a > fan, and that is not a passive cooling effect. > > Given the regression exists since more than 8 years, nobody complained > and at the best of my knowledge there is no bug open in > https://bugzilla.kernel.org, it is reasonable to say it is unused. > > Remove the 'forced_passive' related code. > > Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> Is there any concern with this series ? > --- > .../driver-api/thermal/sysfs-api.rst | 13 --- > drivers/thermal/gov_step_wise.c | 14 +--- > drivers/thermal/thermal_sysfs.c | 80 ------------------- > include/linux/thermal.h | 4 - > 4 files changed, 3 insertions(+), 108 deletions(-) > > diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst > index e7520cb439ac..a4969c474cc3 100644 > --- a/Documentation/driver-api/thermal/sysfs-api.rst > +++ b/Documentation/driver-api/thermal/sysfs-api.rst > @@ -520,19 +520,6 @@ available_policies > > RW, Optional > > -passive > - Attribute is only present for zones in which the passive cooling > - policy is not supported by native thermal driver. Default is zero > - and can be set to a temperature (in millidegrees) to enable a > - passive trip point for the zone. Activation is done by polling with > - an interval of 1 second. > - > - Unit: millidegrees Celsius > - > - Valid values: 0 (disabled) or greater than 1000 > - > - RW, Optional > - > emul_temp > Interface to set the emulated temperature method in thermal zone > (sensor). After setting this temperature, the thermal zone may pass > diff --git a/drivers/thermal/gov_step_wise.c b/drivers/thermal/gov_step_wise.c > index 2ae7198d3067..12acb12aac50 100644 > --- a/drivers/thermal/gov_step_wise.c > +++ b/drivers/thermal/gov_step_wise.c > @@ -109,7 +109,7 @@ static void update_passive_instance(struct thermal_zone_device *tz, > * If value is +1, activate a passive instance. > * If value is -1, deactivate a passive instance. > */ > - if (type == THERMAL_TRIP_PASSIVE || type == THERMAL_TRIPS_NONE) > + if (type == THERMAL_TRIP_PASSIVE) > tz->passive += value; > } > > @@ -122,13 +122,8 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) > bool throttle = false; > int old_target; > > - if (trip == THERMAL_TRIPS_NONE) { > - trip_temp = tz->forced_passive; > - trip_type = THERMAL_TRIPS_NONE; > - } else { > - tz->ops->get_trip_temp(tz, trip, &trip_temp); > - tz->ops->get_trip_type(tz, trip, &trip_type); > - } > + tz->ops->get_trip_temp(tz, trip, &trip_temp); > + tz->ops->get_trip_type(tz, trip, &trip_type); > > trend = get_tz_trend(tz, trip); > > @@ -189,9 +184,6 @@ static int step_wise_throttle(struct thermal_zone_device *tz, int trip) > > thermal_zone_trip_update(tz, trip); > > - if (tz->forced_passive) > - thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE); > - > mutex_lock(&tz->lock); > > list_for_each_entry(instance, &tz->thermal_instances, tz_node) > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index 0866e949339b..4e7f9e880d76 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -216,49 +216,6 @@ trip_point_hyst_show(struct device *dev, struct device_attribute *attr, > return ret ? ret : sprintf(buf, "%d\n", temperature); > } > > -static ssize_t > -passive_store(struct device *dev, struct device_attribute *attr, > - const char *buf, size_t count) > -{ > - struct thermal_zone_device *tz = to_thermal_zone(dev); > - int state; > - > - if (sscanf(buf, "%d\n", &state) != 1) > - return -EINVAL; > - > - /* sanity check: values below 1000 millicelcius don't make sense > - * and can cause the system to go into a thermal heart attack > - */ > - if (state && state < 1000) > - return -EINVAL; > - > - if (state && !tz->forced_passive) { > - if (!tz->passive_delay) > - tz->passive_delay = 1000; > - thermal_zone_device_rebind_exception(tz, "Processor", > - sizeof("Processor")); > - } else if (!state && tz->forced_passive) { > - tz->passive_delay = 0; > - thermal_zone_device_unbind_exception(tz, "Processor", > - sizeof("Processor")); > - } > - > - tz->forced_passive = state; > - > - thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED); > - > - return count; > -} > - > -static ssize_t > -passive_show(struct device *dev, struct device_attribute *attr, > - char *buf) > -{ > - struct thermal_zone_device *tz = to_thermal_zone(dev); > - > - return sprintf(buf, "%d\n", tz->forced_passive); > -} > - > static ssize_t > policy_store(struct device *dev, struct device_attribute *attr, > const char *buf, size_t count) > @@ -403,7 +360,6 @@ static DEVICE_ATTR_RW(sustainable_power); > > /* These thermal zone device attributes are created based on conditions */ > static DEVICE_ATTR_RW(mode); > -static DEVICE_ATTR_RW(passive); > > /* These attributes are unconditionally added to a thermal zone */ > static struct attribute *thermal_zone_dev_attrs[] = { > @@ -438,45 +394,9 @@ static const struct attribute_group thermal_zone_mode_attribute_group = { > .attrs = thermal_zone_mode_attrs, > }; > > -/* We expose passive only if passive trips are present */ > -static struct attribute *thermal_zone_passive_attrs[] = { > - &dev_attr_passive.attr, > - NULL, > -}; > - > -static umode_t thermal_zone_passive_is_visible(struct kobject *kobj, > - struct attribute *attr, > - int attrno) > -{ > - struct device *dev = kobj_to_dev(kobj); > - struct thermal_zone_device *tz; > - enum thermal_trip_type trip_type; > - int count, passive = 0; > - > - tz = container_of(dev, struct thermal_zone_device, device); > - > - for (count = 0; count < tz->trips && !passive; count++) { > - tz->ops->get_trip_type(tz, count, &trip_type); > - > - if (trip_type == THERMAL_TRIP_PASSIVE) > - passive = 1; > - } > - > - if (!passive) > - return attr->mode; > - > - return 0; > -} > - > -static const struct attribute_group thermal_zone_passive_attribute_group = { > - .attrs = thermal_zone_passive_attrs, > - .is_visible = thermal_zone_passive_is_visible, > -}; > - > static const struct attribute_group *thermal_zone_attribute_groups[] = { > &thermal_zone_attribute_group, > &thermal_zone_mode_attribute_group, > - &thermal_zone_passive_attribute_group, > /* This is not NULL terminated as we create the group dynamically */ > }; > > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index c80032322158..a57232a9a6f9 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -131,9 +131,6 @@ struct thermal_cooling_device { > trip point. > * @prev_high_trip: the above current temperature if you've crossed a > passive trip point. > - * @forced_passive: If > 0, temperature at which to switch on all ACPI > - * processor cooling devices. Currently only used by the > - * step-wise governor. > * @need_update: if equals 1, thermal_zone_device_update needs to be invoked. > * @ops: operations this &thermal_zone_device supports > * @tzp: thermal zone parameters > @@ -167,7 +164,6 @@ struct thermal_zone_device { > int passive; > int prev_low_trip; > int prev_high_trip; > - unsigned int forced_passive; > atomic_t need_update; > struct thermal_zone_device_ops *ops; > struct thermal_zone_params *tzp; > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
