Hi Krzysztof, On 2016년 08월 17일 02:51, Krzysztof Kozlowski wrote: > On Tue, Aug 16, 2016 at 09:59:26PM +0900, Chanwoo Choi wrote: >>>> diff --git a/arch/arm64/boot/dts/exynos/exynos5433-tmu.dtsi b/arch/arm64/boot/dts/exynos/exynos5433-tmu.dtsi >>>> new file mode 100644 >>>> index 000000000000..175121db367e >>>> --- /dev/null >>>> +++ b/arch/arm64/boot/dts/exynos/exynos5433-tmu.dtsi >>>> @@ -0,0 +1,306 @@ >>>> +/* >>>> + * Device tree sources for Exynos5433 thermal zone >>>> + * >>>> + * Copyright (c) 2016 Chanwoo Choi <cw00.choi@xxxxxxxxxxx> >>>> + * >>>> + * This program is free software; you can redistribute it and/or modify >>>> + * it under the terms of the GNU General Public License version 2 as >>>> + * published by the Free Software Foundation. >>>> + */ >>>> + >>>> +#include <dt-bindings/thermal/thermal.h> >>>> + >>>> +/ { >>>> +thermal-zones { >>>> + atlas0_thermal: atlas0-thermal { >>>> + thermal-sensors = <&tmu_atlas0>; >>>> + polling-delay-passive = <0>; >>>> + polling-delay = <0>; >>>> + trips { >>>> + atlas0_alert_0: atlas0-alert-0 { >>>> + temperature = <50000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_1: atlas0-alert-1 { >>>> + temperature = <55000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_2: atlas0-alert-2 { >>>> + temperature = <60000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_3: atlas0-alert-3 { >>>> + temperature = <70000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_4: atlas0-alert-4 { >>>> + temperature = <80000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_5: atlas0-alert-5 { >>>> + temperature = <90000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>>> + atlas0_alert_6: atlas0-alert-6 { >>>> + temperature = <95000>; /* millicelsius */ >>>> + hysteresis = <1000>; /* millicelsius */ >>>> + type = "active"; >>>> + }; >>> >>> No critical trip? I think it might be useful to shutdown the system in a >>> user-friendly way. >> >> When I use the critical trip, the following event occur[1]. >> But, I guess that this temperature is not correct temperature >> because after completing the kernel booting, the temperature of big.LITTLE/G3D >> are normal when checking the /sys/class/thermal/thermal_zoneX/temp right after booting. >> - Maintain a uniform temperature(38 ~ 45 millicelsius) right after kernel booting. >> >> I guess that the critical interrupt may occur before initializing the exynos tmu. >> But, I don't spend the many time to check the exynos-tmu.c driver. >> >> [1] >> [ 445.122122] thermal thermal_zone0: critical temperature reached(108 C),shutting down >> [ 445.122399] exynos-tmu 10060000.tmu: Temperature sensor ID: 0xa >> [ 445.122588] exynos-tmu 10060000.tmu: Calibration type is 2-point calibration >> [ 445.127942] reboot: Failed to start orderly shutdown: forcing the issue >> [ 445.134586] Emergency Sync complete >> [ 1.097954] reboot: Power down > > I understand. Apparently the exynos-tmu driver needs some fixes for > this race. Skipping critical then makes sense. > >> >>> >>>> + }; >>>> + >>>> + cooling-maps { >>>> + map0 { >>>> + /* Set maximum frequency as 1800MHz */ >>>> + trip = <&atlas0_alert_0>; >>>> + cooling-device = <&cpu4 1 1>; >>> >>> Out of curiosity: why choosing specific cooling level (so quite fast >>> the device will slow down) instead of letting cooling framework to >>> decide how much to cool? Any particular reason behind this? >> >> This cooling level is just default value in cooling-maps. >> This value is able to overwrite on dts file. >> >> And the thermal subsystem support the cpu cooling features >> with 'cooling-maps'. >> >> Also, when I tested the performance and stress test >> with GLBenchmark, the temperature of big.LITTLE cores/G3D >> reach easily the critical temperature with 8 online cores. >> So, I add the cooling level aggressively to protect >> the system fault of CPU and GPU and to maintain >> the system state. > > I was asking why you do not let cooling framework decide which cooling > level to use but instead you force a specific cooling level. Maybe code > will be a better example. Why not use: > map0 { > /* Set maximum frequency as 1800MHz */ > trip = <&atlas0_alert_0>; > cooling-device = <&cpu4 0 1>; > } > map1 { > /* Set maximum frequency as 1700MHz */ > trip = <&atlas0_alert_1>; > cooling-device = <&cpu4 1 2>; > }; > > For higher frequencies it makes even more sense: > map6 { > /* Set maximum frequency as 800MHz */ > trip = <&atlas0_alert_6>; > cooling-device = <&cpu4 7 11>; > }; > > which allows the system to use suitable cooling level to maintain the > balance between performance and temperature dissipance, instead of some > fixed cooling level which might not be accurate to the system load. Ah. I misunderstand of your question. OK. I'll expand the range of cooling level as you suggested. Best Regards, Chanwoo Choi -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html