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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
 Daniel Lezcano <daniel.lezcano@linaro.org>,
 Lukasz Luba <lukasz.luba@arm.com>,
 Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Subject:
 [PATCH v1 09/16] thermal: gov_step_wise: Use trip thresholds instead of trip
 temperatures
Date: Wed, 10 Apr 2024 18:43:07 +0200
Message-ID: <3769085.MHq7AAxBmi@kreacher>
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

In principle, the Step-Wise governor should take trip hystereses into
account.  After all, once a trip has been crossed on the way up,
mitigation is still needed until it is crossed on the way down.

For this reason, make it use trip thresholds that are computed by
the core when trips are crossed, so as to apply mitigations in the
hysteresis rages of trips that were crossed on the way up, but have
not been crossed on the way down yet.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/thermal/gov_step_wise.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Index: linux-pm/drivers/thermal/gov_step_wise.c
===================================================================
--- linux-pm.orig/drivers/thermal/gov_step_wise.c
+++ linux-pm/drivers/thermal/gov_step_wise.c
@@ -62,7 +62,8 @@ static unsigned long get_target_state(st
 }
 
 static void thermal_zone_trip_update(struct thermal_zone_device *tz,
-				     const struct thermal_trip *trip)
+				     const struct thermal_trip *trip,
+				     int trip_threshold)
 {
 	int trip_id = thermal_zone_trip_id(tz, trip);
 	enum thermal_trend trend;
@@ -72,13 +73,13 @@ static void thermal_zone_trip_update(str
 
 	trend = get_tz_trend(tz, trip);
 
-	if (tz->temperature >= trip->temperature) {
+	if (tz->temperature >= trip_threshold) {
 		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);
+		trip_id, trip->type, trip_threshold, trend, throttle);
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
 		if (instance->trip != trip)
@@ -131,7 +132,7 @@ static void step_wise_manage(struct ther
 		    trip->type == THERMAL_TRIP_HOT)
 			continue;
 
-		thermal_zone_trip_update(tz, trip);
+		thermal_zone_trip_update(tz, trip, td->threshold);
 	}
 
 	list_for_each_entry(instance, &tz->thermal_instances, tz_node)