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Date: Tue, 15 Dec 2020 00:38:04 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: daniel.lezcano@...aro.org, rui.zhang@...el.com
Cc: mjg59@...on.org.uk, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, amitk@...nel.org,
thara.gopinath@...aro.org, Jonathan Corbet <corbet@....net>,
Viresh Kumar <viresh.kumar@...aro.org>,
linux-doc@...r.kernel.org (open list:DOCUMENTATION)
Subject: [PATCH 1/6] thermal/core: Remove the 'forced_passive' option
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@...aro.org>
---
.../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;
--
2.25.1
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