Adjust fan speed gently while in the optimal range when temperature is drifting to minimise overshoot in either direction.
diff --git a/adl.c b/adl.c
index cb79c59..198e1ed 100644
--- a/adl.c
+++ b/adl.c
@@ -869,6 +869,18 @@ static void fan_autotune(int gpu, int temp, int fanpercent, bool *fan_optimal)
if (opt_debug)
applog(LOG_DEBUG, "Temperature %d degrees below target, decreasing fanspeed", opt_hysteresis);
newpercent = ga->targetfan - 1;
+ } else {
+ /* We're in the optimal range, make minor adjustments if the
+ * temp is still drifting */
+ if (fanpercent > bot && temp < ga->lasttemp && temp < ga->targettemp) {
+ if (opt_debug)
+ applog(LOG_DEBUG, "Temperature dropping while in target range, decreasing fanspeed");
+ newpercent = ga->targetfan - 1;
+ } else if (fanpercent < top && temp > ga->lasttemp && temp > ga->targettemp - opt_hysteresis) {
+ if (opt_debug)
+ applog(LOG_DEBUG, "Temperature rising while in target range, increasing fanspeed");
+ newpercent = ga->targetfan + 1;
+ }
}
if (newpercent > iMax)