On 24/06/2021 11:59, Eric Woudstra wrote: > > For Marvell: > > https://www.google.com/url?sa=t&source=web&rct=j&url=https://wiki.kobol.io/helios4/files/som/brochure_a38x_microsom_2017-09-05.pdf > > Armada38x maximum die temperature 115 degrees Celcius. They really get hotter then 100. > > But for mt7622 I cannot find this value Found that: https://download.kamami.pl/p579344-MT7622A_Datasheet_for_BananaPi_Only%281%29.pdf Chapter 3.3 - Thermal Characteristics Given the values I suggest: - Passive - 80°C - Hot - 90°C - Critical - 100°C And passive polling set to 250ms. It sounds like the sensor is not supporting the interrupt mode yet, so a big gap is needed with the Tj IMO to give the time to detect the trip point crossing with the polling. > Get BlueMail for Android > > On Jun 23, 2021, 10:08 PM, at 10:08 PM, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote: >> On 23/06/2021 20:43, Eric Woudstra wrote: >>> >>> I choose "hot" before, because 87 degrees seems ok to start frequency >>> throttling. But, yes, it should be passive. >>> >>> 87 is still quite low if I compare this temperature with the >>> wrt3200acm Marvell dual core arm soc. They even went above 100 >>> degrees so I feel for an arm processor inside a router box it is fine >>> to use 87 degrees But maybe someone at Mediatek can give some more >>> details about operating temperatures. >> >> Sometimes, the SoC vendor puts a high temperature in the DT just to >> export the thermal zone and deal with it from userspace. So putting the >> high temp allow the userspace (usually a thermal engine - Android >> stuff) >> to deal with the mitigation without a kernel interaction. >> >> Having more than 100°C could be this kind of setup. Only the operating >> temperature from the hardware documentation will tell the safe >> temperature for the silicon. >> >> IMO, 77°C is a good compromise until getting the documented temp. 87°C >> sounds to me a bit too hot. >> >>> It may be possible to leave the active map in the device tree as some >>> users of the bananapi might choose to install a fan as it is one of >>> the options. >> >> The active trip only makes sense if the cooling device is a fan (or any >> active device), so the mapping points to a fan node, like: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399-khadas-edge.dtsi#n192 >> >> If there is no such [pwm] fan output on the board, no active trip point >> should be added. >> >>> Get BlueMail for Android >>> >>> On Jun 23, 2021, 5:58 PM, at 5:58 PM, Daniel Lezcano >>> <daniel.lezcano@xxxxxxxxxx> wrote: >>>> On 23/06/2021 17:35, Eric Woudstra wrote: >>>>> It is only useful to set 1 map with the regulated temperature for >>>>> cpu frequency throttling. Same as in the kernel document >>>>> example. >>>>> >>>>> >>>>> It has no use to set frequency scaling on 2 different >>>>> temperature trip points, as the lowest one makes sure the higher >>>>> one(s) are never reached. >>>> >>>> I looked more closely the DT and there is a misunderstanding of >>>> the thermal framework in the definition. >>>> >>>> There is one trip point with the passive type and the cpu cooling >>>> device, followed by a second trip point with the active type *but* >>>> the same cpu cooling device. That is wrong. >>>> >>>> And finally, there is the hot trip point as a third mapping and >>>> the same cooling device. >>>> >>>> The hot trip point is only there to notify userspace and let it >>>> take an immediate action to prevent an emergency shutdown when >>>> reaching the critical temperature. >>>> >>>>> It can be applied only at 1 trip point. Multiple trip points is >>>>> only usefully for fan control to make sure the fan is not too >>>>> noisy when it is not necessary to be noisy. >>>>> >>>>> >>>>> The CPU will almost come to a dead stop when it starts to pass >>>>> the lowest thermal map with frequency throttling. >>>>> >>>>> This is why it is a bug and needs a fix, not only adjustment. >>>> >>>> Yes, you are right. It should be something like (verbatim copy): >>>> >>>> diff --git a/arch/arm64/boot/dts/mediatek/mt7622.dtsi >>>> b/arch/arm64/boot/dts/mediatek/mt7622.dtsi index >>>> 890a942ec608..88c81d24f4ff 100644 --- >>>> a/arch/arm64/boot/dts/mediatek/mt7622.dtsi +++ >>>> b/arch/arm64/boot/dts/mediatek/mt7622.dtsi @@ -136,24 +136,18 @@ >>>> secmon_reserved: secmon@43000000 { >>>> >>>> thermal-zones { cpu_thermal: cpu-thermal { - >>>> polling-delay-passive = <1000>; + polling-delay-passive = <250>; >>>> polling-delay = <1000>; >>>> >>>> thermal-sensors = <&thermal 0>; >>>> >>>> trips { cpu_passive: cpu-passive { - temperature = <47000>; + >>>> temperature = <77000>; hysteresis = <2000>; type = "passive"; }; >>>> >>>> - cpu_active: cpu-active { - temperature = <67000>; - >>>> hysteresis = <2000>; - type = "active"; - }; - cpu_hot: >>>> cpu-hot { temperature = <87000>; hysteresis = <2000>; @@ -173,18 >>>> +167,6 @@ map0 { cooling-device = <&cpu0 THERMAL_NO_LIMIT >>>> THERMAL_NO_LIMIT>, <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; }; - >>>> - map1 { - trip = <&cpu_active>; - cooling-device = >>>> <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>, - <&cpu1 >>>> THERMAL_NO_LIMIT THERMAL_NO_LIMIT>; - }; - - map2 { - >>>> trip = <&cpu_hot>; - cooling-device = <&cpu0 THERMAL_NO_LIMIT >>>> THERMAL_NO_LIMIT>, - <&cpu1 THERMAL_NO_LIMIT >>>> THERMAL_NO_LIMIT>; - }; }; }; }; >>>> >>>> >>>> -- <http://www.linaro.org/> Linaro.org │ Open source software for >>>> ARM SoCs >>>> >>>> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | >>>> <http://twitter.com/#!/linaroorg> Twitter | >>>> <http://www.linaro.org/linaro-blog/> Blog >>> >> >> >> -- >> <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs >> >> Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | >> <http://twitter.com/#!/linaroorg> Twitter | >> <http://www.linaro.org/linaro-blog/> Blog > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
