openwrt/target/linux/bcm27xx/patches-4.19/950-0153-drivers-thermal-step_wise-add-support-for-hysteresis.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

97 lines
3.4 KiB
Diff

From 05a13bbd7fbb76b4f690042173749a55d85de831 Mon Sep 17 00:00:00 2001
From: Ram Chandrasekar <rkumbako@codeaurora.org>
Date: Mon, 7 May 2018 11:54:08 -0600
Subject: [PATCH] drivers: thermal: step_wise: add support for
hysteresis
From: Ram Chandrasekar <rkumbako@codeaurora.org>
Step wise governor increases the mitigation level when the temperature
goes above a threshold and will decrease the mitigation when the
temperature falls below the threshold. If it were a case, where the
temperature hovers around a threshold, the mitigation will be applied
and removed at every iteration. This reaction to the temperature is
inefficient for performance.
The use of hysteresis temperature could avoid this ping-pong of
mitigation by relaxing the mitigation to happen only when the
temperature goes below this lower hysteresis value.
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
---
drivers/thermal/step_wise.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
--- a/drivers/thermal/step_wise.c
+++ b/drivers/thermal/step_wise.c
@@ -36,7 +36,7 @@
* for this trip point
* d. if the trend is THERMAL_TREND_DROP_FULL, use lower limit
* for this trip point
- * If the temperature is lower than a trip point,
+ * If the temperature is lower than a hysteresis temperature,
* a. if the trend is THERMAL_TREND_RAISING, do nothing
* b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
* state for this trip point, if the cooling state already
@@ -127,7 +127,7 @@ static void update_passive_instance(stru
static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
{
- int trip_temp;
+ int trip_temp, hyst_temp;
enum thermal_trip_type trip_type;
enum thermal_trend trend;
struct thermal_instance *instance;
@@ -135,22 +135,23 @@ static void thermal_zone_trip_update(str
int old_target;
if (trip == THERMAL_TRIPS_NONE) {
- trip_temp = tz->forced_passive;
+ hyst_temp = trip_temp = tz->forced_passive;
trip_type = THERMAL_TRIPS_NONE;
} else {
tz->ops->get_trip_temp(tz, trip, &trip_temp);
+ hyst_temp = trip_temp;
+ if (tz->ops->get_trip_hyst) {
+ tz->ops->get_trip_hyst(tz, trip, &hyst_temp);
+ hyst_temp = trip_temp - hyst_temp;
+ }
tz->ops->get_trip_type(tz, trip, &trip_type);
}
trend = get_tz_trend(tz, trip);
- if (tz->temperature >= trip_temp) {
- throttle = true;
- trace_thermal_zone_trip(tz, trip, trip_type);
- }
-
- dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
- trip, trip_type, trip_temp, trend, throttle);
+ dev_dbg(&tz->device,
+ "Trip%d[type=%d,temp=%d,hyst=%d]:trend=%d,throttle=%d\n",
+ trip, trip_type, trip_temp, hyst_temp, trend, throttle);
mutex_lock(&tz->lock);
@@ -159,6 +160,18 @@ static void thermal_zone_trip_update(str
continue;
old_target = instance->target;
+ throttle = false;
+ /*
+ * Lower the mitigation only if the temperature
+ * goes below the hysteresis temperature.
+ */
+ if (tz->temperature >= trip_temp ||
+ (tz->temperature >= hyst_temp &&
+ old_target != THERMAL_NO_TARGET)) {
+ throttle = true;
+ trace_thermal_zone_trip(tz, trip, trip_type);
+ }
+
instance->target = get_target_state(instance, trend, throttle);
dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n",
old_target, (int)instance->target);