openwrt/target/linux/mvebu/patches-6.6/350-drivers-thermal-step_wise-add-support-for-hysteresis.patch
Daniel Golle ac783b419b mvebu: improve thermal management of IEI Puzzle devices
- Make step_wise thermal governor respect hysteresis
   This is done by importing a downstream patch, backporting the same feature
   now present in Linux v6.10+ would be too messy.
 - Introduce thermal zone for the WT61P803 uC (chassis and board sensors)
 - Introduce thermal zones for AQR NBase-T PHYs
 - No longer modify existing SoC thermal zones (which are now only in charge
   for emergency shutdown, and can be interrupt driven instead of polled)

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
2024-06-01 16:40:10 +01:00

66 lines
2.5 KiB
Diff

From 9685ce100f0d302501117113ef0a526ad1acca1d 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
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>
[forward-ported for Linux 6.6, as stop-gap downstream solution]
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
drivers/thermal/gov_step_wise.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
--- a/drivers/thermal/gov_step_wise.c
+++ b/drivers/thermal/gov_step_wise.c
@@ -86,22 +86,31 @@ static void thermal_zone_trip_update(str
struct thermal_instance *instance;
bool throttle = false;
int old_target;
+ int hyst_temp;
trend = get_tz_trend(tz, trip_id);
- if (tz->temperature >= trip->temperature) {
- throttle = true;
- trace_thermal_zone_trip(tz, trip_id, trip->type);
- }
-
- dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d]:trend=%d,throttle=%d\n",
- trip_id, trip->type, trip->temperature, trend, throttle);
+ hyst_temp = trip->temperature - trip->hysteresis;
+ dev_dbg(&tz->device, "Trip%d[type=%d,temp=%d,hyst=%d]:trend=%d,throttle=%d\n",
+ trip_id, trip->type, trip->temperature, hyst_temp, trend, throttle);
list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
if (instance->trip != trip)
continue;
old_target = instance->target;
+ throttle = false;
+ /*
+ * Lower the mitigation only if the temperature
+ * goes below the hysteresis temperature.
+ */
+ if (tz->temperature >= trip->temperature ||
+ (tz->temperature >= hyst_temp &&
+ old_target != THERMAL_NO_TARGET)) {
+ throttle = true;
+ trace_thermal_zone_trip(tz, trip_id, 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);