quoted

quoted

IIUC, the resulting change will be an on/off action. The thermal zone
is mitigated with the highest cooling effect, so the lowest OPP, then
the temperature trend is stable until it goes below the trip - margin
where the mitigation is stopped.

Yes, your understanding is correctly, once the temperature exceeds
passive trip point, the highest cooling action will be applied
immediately and then it will be stable there until temperature drop to
trip - margin, then the cooling action will be cancelled, the margin is to avoid

the back and forth near the passive trip point.

quoted

quoted

Except, I'm missing something, setting a trip point with a 10000
hysteresis and a cooling map min/max set to the highest opp will result on

the same.

quoted

Yes setting cooling map min/max cooling state to highest OPP will make
the highest cooling action applied immediately, and to have the
function of cooling action being cancelled when temperature drops to
trip - margin, I have to define another trip point, say passive trip
point is 85000, and cooling map min/max set to highest OPP in passive
trip point then add another trip point named "active" with 75000, and

without any cooling map in it, right?

May be I misunderstood but only the change as below is needed. No need to
add a trip point, especially an 'active' trip which is a for an active cooling
device like a fan.

diff --git a/arch/arm64/boot/dts/freescale/imx8mm.dtsi

b/arch/arm64/boot/dts/freescale/imx8mm.dtsi
index cc7152ecedd9..bea263bd06b4 100644

--- a/arch/arm64/boot/dts/freescale/imx8mm.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mm.dtsi

@@ -231,10 +231,10 @@ cooling-maps {
 				map0 {
 					trip = <&cpu_alert0>;
 					cooling-device =
-						<&A53_0 THERMAL_NO_LIMIT

THERMAL_NO_LIMIT>,
-						<&A53_1 THERMAL_NO_LIMIT
THERMAL_NO_LIMIT>,
-						<&A53_2 THERMAL_NO_LIMIT
THERMAL_NO_LIMIT>,
-						<&A53_3 THERMAL_NO_LIMIT
THERMAL_NO_LIMIT>;
+						<&A53_0 2 2>,
+						<&A53_1 2 2>,
+						<&A53_2 2 2>,
+						<&A53_3 2 2>
 				};
 			};
 		};