diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0157-drivers-thermal-step_wise-add-support-for-hysteresis.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0157-drivers-thermal-step_wise-add-support-for-hysteresis.patch | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0157-drivers-thermal-step_wise-add-support-for-hysteresis.patch b/target/linux/brcm2708/patches-4.19/950-0157-drivers-thermal-step_wise-add-support-for-hysteresis.patch new file mode 100644 index 0000000000..af447c1704 --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0157-drivers-thermal-step_wise-add-support-for-hysteresis.patch @@ -0,0 +1,96 @@ +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); |