linux-kernel - [PATCH v3 4/6] thermal: core: Send trip crossing notifications at init time if needed

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Date: Tue, 02 Apr 2024 21:02:10 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM <linux-pm@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Lukasz Luba <lukasz.luba@....com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Subject:
 [PATCH v3 4/6] thermal: core: Send trip crossing notifications at init time
 if needed

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

If a trip point is already exceeded by the zone temperature at the
initialization time, no trip crossing notification is send regarding
this even though mitigation should be started then.

Address this by rearranging the code in handle_thermal_trip() to
send a trip crossing notification for trip points already exceeded
by the zone temperature initially which also allows to reduce its
size by using the observation that the initialization and regular
trip crossing on the way up become the same case then.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

v2 -> v3: New patch

---
 drivers/thermal/thermal_core.c |   37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

Index: linux-pm/drivers/thermal/thermal_core.c
===================================================================
--- linux-pm.orig/drivers/thermal/thermal_core.c
+++ linux-pm/drivers/thermal/thermal_core.c
@@ -364,6 +364,7 @@ static void handle_thermal_trip(struct t
 				struct thermal_trip_desc *td)
 {
 	const struct thermal_trip *trip = &td->trip;
+	int old_threshold;
 
 	if (trip->temperature == THERMAL_TEMP_INVALID)
 		return;
@@ -375,25 +376,11 @@ static void handle_thermal_trip(struct t
 	 * is what needs to be compared with the previous zone temperature
 	 * to decide which action to take.
 	 */
-	if (tz->last_temperature == THERMAL_TEMP_INVALID) {
-		/* Initialization. */
-		td->threshold = trip->temperature;
-		if (tz->temperature >= td->threshold)
-			td->threshold -= trip->hysteresis;
-	} else if (tz->last_temperature < td->threshold) {
-		/*
-		 * There is no mitigation under way, so it needs to be started
-		 * if the zone temperature exceeds the trip one.  The new
-		 * threshold is then set to the low temperature of the trip.
-		 */
-		if (tz->temperature >= trip->temperature) {
-			thermal_notify_tz_trip_up(tz, trip);
-			thermal_debug_tz_trip_up(tz, trip);
-			td->threshold = trip->temperature - trip->hysteresis;
-		} else {
-			td->threshold = trip->temperature;
-		}
-	} else {
+	old_threshold = td->threshold;
+	td->threshold = trip->temperature;
+
+	if (tz->last_temperature >= old_threshold &&
+	    tz->last_temperature != THERMAL_TEMP_INVALID) {
 		/*
 		 * Mitigation is under way, so it needs to stop if the zone
 		 * temperature falls below the low temperature of the trip.
@@ -402,10 +389,18 @@ static void handle_thermal_trip(struct t
 		if (tz->temperature < trip->temperature - trip->hysteresis) {
 			thermal_notify_tz_trip_down(tz, trip);
 			thermal_debug_tz_trip_down(tz, trip);
-			td->threshold = trip->temperature;
 		} else {
-			td->threshold = trip->temperature - trip->hysteresis;
+			td->threshold -= trip->hysteresis;
 		}
+	} else if (tz->temperature >= trip->temperature) {
+		/*
+		 * There is no mitigation under way, so it needs to be started
+		 * if the zone temperature exceeds the trip one.  The new
+		 * threshold is then set to the low temperature of the trip.
+		 */
+		thermal_notify_tz_trip_up(tz, trip);
+		thermal_debug_tz_trip_up(tz, trip);
+		td->threshold -= trip->hysteresis;
 	}
 
 	if (trip->type == THERMAL_TRIP_CRITICAL || trip->type == THERMAL_TRIP_HOT)