diff mbox series

Fix mt7622.dtsi thermal cpu

Message ID 20210619121927.32699-1-ericwouds@gmail.com (mailing list archive)
State New, archived
Headers show
Series Fix mt7622.dtsi thermal cpu | expand

Commit Message

Eric Woudstra June 19, 2021, 12:19 p.m. UTC
From: Eric Woudstra <ericwouds@gmail.com>

Cpu-thermal is set to use all frequencies already at 47 degrees. 
Using the CPU at 50 for a minute, the CPU has reached 48 degrees, is 
throttled back to lowest setting, making the mt7622 terrribly slow. 
Even at this low speed, the CPU does not cool down lower then 47 so
the CPU is stuck at lowest possible frequency until it shut down and
stays off for 15 minutes.

cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
                 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;

This should not be set al every cooling map. It should only be set at
the highest cooling map. Same as in the example:

https://www.kernel.org/doc/Documentation/devicetree/bindings/
thermal/thermal.txt  line 272

But then without the fan and added a third map.

Now temperature will be regulated at 87 degrees celcius. At temperatures
lower then 87, all frequencies can be used.

Also see the post:

http://forum.banana-pi.org/t/bpi-r64-only-10-cpu-speed-at-already-48-
degrees-celcius-speed-not-increasing-anymore/12262

Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
---
 arch/arm64/boot/dts/mediatek/mt7622.dtsi | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

Daniel Lezcano June 21, 2021, 6:29 p.m. UTC | #1
On 19/06/2021 14:19, ericwouds@gmail.com wrote:
> From: Eric Woudstra <ericwouds@gmail.com>
> 
> Cpu-thermal is set to use all frequencies already at 47 degrees. 
> Using the CPU at 50 for a minute, the CPU has reached 48 degrees, is 
> throttled back to lowest setting, making the mt7622 terrribly slow. 
> Even at this low speed, the CPU does not cool down lower then 47 so
> the CPU is stuck at lowest possible frequency until it shut down and
> stays off for 15 minutes.
> 
> cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
>                  <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> 
> This should not be set al every cooling map. It should only be set at
> the highest cooling map. Same as in the example:
> 
> https://www.kernel.org/doc/Documentation/devicetree/bindings/
> thermal/thermal.txt  line 272
> 
> But then without the fan and added a third map.
> 
> Now temperature will be regulated at 87 degrees celcius. At temperatures
> lower then 87, all frequencies can be used.

47°C is really a too low temperature and this performance drop is normal.

I would not remove the passive mitigation but try by increasing the CPU
temp to 70°C and by changing the active trip point to 80°C. If it works
fine, try 75°C and 85°C.

To test, the thermal killer is dhrystone (one thread per cpu).

With a 75°C passive trip point, the step wise thermal governor, I think
the mitigation will happen smoothly providing better performances, and
probably the fan won't fire.

> Also see the post:
> 
> http://forum.banana-pi.org/t/bpi-r64-only-10-cpu-speed-at-already-48-
> degrees-celcius-speed-not-increasing-anymore/12262
> 
> Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
> ---
>  arch/arm64/boot/dts/mediatek/mt7622.dtsi | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/mediatek/mt7622.dtsi b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> index 890a942ec..b779c7aa6 100644
> --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> @@ -170,14 +170,14 @@ cpu-crit {
>  			cooling-maps {
>  				map0 {
>  					trip = <&cpu_passive>;
> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +					cooling-device = <&cpu0 0 0>,
> +							 <&cpu1 0 0>;
>  				};
>  
>  				map1 {
>  					trip = <&cpu_active>;
> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +					cooling-device = <&cpu0 0 0>,
> +							 <&cpu1 0 0>;
>  				};
>  
>  				map2 {
>
Eric Woudstra June 23, 2021, 3:35 p.m. UTC | #2
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. 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.




There is no fan... On the bpi r64.


Anyway without throttling at all a kernel build for more then an hour temperature creeps up to 85 degrees.

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On Jun 21, 2021, 8:29 PM, at 8:29 PM, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
>On 19/06/2021 14:19, ericwouds@gmail.com wrote:
>> From: Eric Woudstra <ericwouds@gmail.com>
>> 
>> Cpu-thermal is set to use all frequencies already at 47 degrees. 
>> Using the CPU at 50 for a minute, the CPU has reached 48 degrees, is 
>> throttled back to lowest setting, making the mt7622 terrribly slow. 
>> Even at this low speed, the CPU does not cool down lower then 47 so
>> the CPU is stuck at lowest possible frequency until it shut down and
>> stays off for 15 minutes.
>> 
>> cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
>>                  <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>> 
>> This should not be set al every cooling map. It should only be set at
>> the highest cooling map. Same as in the example:
>> 
>> https://www.kernel.org/doc/Documentation/devicetree/bindings/
>> thermal/thermal.txt  line 272
>> 
>> But then without the fan and added a third map.
>> 
>> Now temperature will be regulated at 87 degrees celcius. At
>temperatures
>> lower then 87, all frequencies can be used.
>
>47°C is really a too low temperature and this performance drop is
>normal.
>
>I would not remove the passive mitigation but try by increasing the CPU
>temp to 70°C and by changing the active trip point to 80°C. If it works
>fine, try 75°C and 85°C.
>
>To test, the thermal killer is dhrystone (one thread per cpu).
>
>With a 75°C passive trip point, the step wise thermal governor, I think
>the mitigation will happen smoothly providing better performances, and
>probably the fan won't fire.
>
>> Also see the post:
>> 
>> http://forum.banana-pi.org/t/bpi-r64-only-10-cpu-speed-at-already-48-
>> degrees-celcius-speed-not-increasing-anymore/12262
>> 
>> Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
>> ---
>>  arch/arm64/boot/dts/mediatek/mt7622.dtsi | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>> 
>> diff --git a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
>b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
>> index 890a942ec..b779c7aa6 100644
>> --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
>> +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
>> @@ -170,14 +170,14 @@ cpu-crit {
>>  			cooling-maps {
>>  				map0 {
>>  					trip = <&cpu_passive>;
>> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
>> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>> +					cooling-device = <&cpu0 0 0>,
>> +							 <&cpu1 0 0>;
>>  				};
>>  
>>  				map1 {
>>  					trip = <&cpu_active>;
>> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
>> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>> +					cooling-device = <&cpu0 0 0>,
>> +							 <&cpu1 0 0>;
>>  				};
>>  
>>  				map2 {
>> 
>
>
>-- 
><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
Daniel Lezcano June 23, 2021, 3:58 p.m. UTC | #3
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>;
-				};
 			};
 		};
 	};
Eric Woudstra June 23, 2021, 6:43 p.m. UTC | #4
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.

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.

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On Jun 23, 2021, 5:58 PM, at 5:58 PM, Daniel Lezcano <daniel.lezcano@linaro.org> 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
Daniel Lezcano June 23, 2021, 8:08 p.m. UTC | #5
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@linaro.org> 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
>
Eric Woudstra June 24, 2021, 9:59 a.m. UTC | #6
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

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On Jun 23, 2021, 10:08 PM, at 10:08 PM, Daniel Lezcano <daniel.lezcano@linaro.org> 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@linaro.org> 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
Daniel Lezcano June 24, 2021, 10:21 a.m. UTC | #7
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@linaro.org> 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@linaro.org> 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
>
Eric Woudstra June 24, 2021, 1:29 p.m. UTC | #8
The SOC runs unthrotlled slowly to 80 degrees. This takes minutes. Polling interval 1 second or less does not matter much when looking at these temperature rise times 

After that in more then an hour it slowly creeps up to 85. I believe the design is so that the SOC, under normal circumstances, can run at 1.35 GHz without throttling frequency, without heatsink. It just needs a safeguard for different circumstances.

Most of these SOCs can also run in industrial grade circumstances, which means up to 85 degrees ambient temperature already . If not industrial then this would be 60 degrees ambient already 

But only someone at Mediatek can confirm this 

⁣Get BlueMail for Android ​

On Jun 24, 2021, 12:21 PM, at 12:21 PM, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
>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@linaro.org> 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@linaro.org> 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
Daniel Golle June 25, 2021, 9:22 a.m. UTC | #9
On Fri, Jun 25, 2021 at 10:16:43AM +0200, Frank Wunderlich wrote:
> Hi,
> 
> > Gesendet: Donnerstag, 24. Juni 2021 um 15:29 Uhr
> > Von: "Eric Woudstra" <ericwouds@gmail.com>
> > The SOC runs unthrotlled slowly to 80 degrees. This takes minutes. Polling interval 1 second or less does not matter much when looking at these temperature rise times 
> > 
> > After that in more then an hour it slowly creeps up to 85. I believe the design is so that the SOC, under normal circumstances, can run at 1.35 GHz without throttling frequency, without heatsink. It just needs a safeguard for different circumstances.
> > 
> > Most of these SOCs can also run in industrial grade circumstances, which means up to 85 degrees ambient temperature already . If not industrial then this would be 60 degrees ambient already 
> > 
> > But only someone at Mediatek can confirm this 
> 
> maybe Matthias knows anybody?
> get_maintainers-script shows no mtk employee for mtk_thermal driver, added Sean and Ryder as common Linux-Contacts...
> 
> Daniel from openwrt have some other mt7622 Boards maybe he can test the Fan approach below

I got Linksys E8450 aka. Belkin RT3200 ( https://fcc.io/K7S-03571 ) as
well as Ubiquiti UniFi 6 LR ( https://fcc.io/SWX-U6LR ). Both got quite
massive customized heatsinks (see internal photos on FCC submission),
which results in much better heat dissipation than just having the
naked chip like on the BPi-R64.
Hence I also can't test the fan approach on boards other than the R64.


> 
> > On Jun 24, 2021, 12:21 PM, at 12:21 PM, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
> > >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
> 
> maybe adding FAN (r64, don't know for other mt7622 boards) for lower 2 trips (with adjusted temperature points) and cpu-throtteling for upper 2 trips
> 
> something like this (used the 70/80 trip points discussed before):
> 
> --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> @@ -134,6 +134,13 @@
>  		};
>  	};
>  
> +	fan0: pwm-fan {
> +		compatible = "pwm-fan";
> +		#cooling-cells = <2>;
> +		pwms = <&pwm 2 10000 0>;
> +		cooling-levels = <0 102 170 230>;
> +	};
> +
>  	thermal-zones {
>  		cpu_thermal: cpu-thermal {
>  			polling-delay-passive = <1000>;
> @@ -143,13 +150,13 @@
>  
>  			trips {
>  				cpu_passive: cpu-passive {
> -					temperature = <47000>;
> +					temperature = <70000>;
>  					hysteresis = <2000>;
>  					type = "passive";
>  				};
>  
>  				cpu_active: cpu-active {
> -					temperature = <67000>;
> +					temperature = <80000>;
>  					hysteresis = <2000>;
>  					type = "active";
>  				};
> @@ -170,14 +177,12 @@
>  			cooling-maps {
>  				map0 {
>  					trip = <&cpu_passive>;
> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +					cooling-device = <&fan0 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>;
> +					cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>  				};
>  
>  				map2 {
> @@ -428,6 +433,7 @@
>  	pwm: pwm@11006000 {
>  		compatible = "mediatek,mt7622-pwm";
>  		reg = <0 0x11006000 0 0x1000>;
> +		#pwm-cells = <3>;
>  		interrupts = <GIC_SPI 77 IRQ_TYPE_LEVEL_LOW>;
>  		clocks = <&topckgen CLK_TOP_PWM_SEL>,
>  			 <&pericfg CLK_PERI_PWM_PD>,
> 
> 
> regards Frank
Frank Wunderlich June 25, 2021, 9:31 a.m. UTC | #10
> Gesendet: Freitag, 25. Juni 2021 um 11:22 Uhr
> Von: "Daniel Golle" <daniel@makrotopia.org>

> On Fri, Jun 25, 2021 at 10:16:43AM +0200, Frank Wunderlich wrote:
> > Daniel from openwrt have some other mt7622 Boards maybe he can test the Fan approach below
>
> I got Linksys E8450 aka. Belkin RT3200 ( https://fcc.io/K7S-03571 ) as
> well as Ubiquiti UniFi 6 LR ( https://fcc.io/SWX-U6LR ). Both got quite
> massive customized heatsinks (see internal photos on FCC submission),
> which results in much better heat dissipation than just having the
> naked chip like on the BPi-R64.
> Hence I also can't test the fan approach on boards other than the R64.

Do your both mt7622 boards miss the fan-socket or is it not connected to pwm3? then we need to move the fan-parts to mt7622-bananapi-r64.dts instead of mt7622.dtsi

regards Frank
Daniel Lezcano June 25, 2021, 9:57 a.m. UTC | #11
Hi Frank,

On 25/06/2021 10:16, Frank Wunderlich wrote:
> Hi,
> 

>> Gesendet: Donnerstag, 24. Juni 2021 um 15:29 Uhr Von: "Eric
>> Woudstra" <ericwouds@gmail.com> The SOC runs unthrotlled slowly to
>> 80 degrees. This takes minutes.
Polling interval 1 second or less does not matter much when looking at
these temperature rise times
>> 
>> After that in more then an hour it slowly creeps up to 85. I
>> believe
the design is so that the SOC, under normal circumstances, can run at
1.35 GHz without throttling frequency, without heatsink. It just needs a
safeguard for different circumstances.
>> 
>> Most of these SOCs can also run in industrial grade circumstances,
which means up to 85 degrees ambient temperature already . If not
industrial then this would be 60 degrees ambient already
>> 
>> But only someone at Mediatek can confirm this
> 
> maybe Matthias knows anybody? get_maintainers-script shows no mtk
> employee for mtk_thermal driver,
added Sean and Ryder as common Linux-Contacts...
> 
> Daniel from openwrt have some other mt7622 Boards maybe he can test
the Fan approach below
> 
>> On Jun 24, 2021, 12:21 PM, at 12:21 PM, Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>>> 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
> 
> maybe adding FAN (r64, don't know for other mt7622 boards) for lower
> 2
trips (with adjusted temperature points) and cpu-throtteling for upper 2
trips

It depends what you want to achieve first:

 - better / sustained performance, then fan before

 - quiet device or power saving (on battery) then cpu throttling before

That is board specific, it should be tuned on DT board specific file.

Some comments below:

> something like this (used the 70/80 trip points discussed before):
> --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
> +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi

You should not add the fan in the mt7622.dtsi itself but in the board
specific file where there is a fan output on it. mt7622.dtsi is supposed
to be the SoC itself AFAICT.

For instance:

https://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399-sapphire.dtsi#n39

https://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399-sapphire.dtsi#n164

> @@ -134,6 +134,13 @@
>  		};
>  	};
>  
> +	fan0: pwm-fan {
> +		compatible = "pwm-fan";
> +		#cooling-cells = <2>;
> +		pwms = <&pwm 2 10000 0>;
> +		cooling-levels = <0 102 170 230>;
> +	};
> +
>  	thermal-zones {
>  		cpu_thermal: cpu-thermal {
>  			polling-delay-passive = <1000>;
> @@ -143,13 +150,13 @@
>  
>  			trips {
>  				cpu_passive: cpu-passive {
> -					temperature = <47000>;
> +					temperature = <70000>;
>  					hysteresis = <2000>;
>  					type = "passive";
>  				};
>  
>  				cpu_active: cpu-active {
> -					temperature = <67000>;
> +					temperature = <80000>;
>  					hysteresis = <2000>;
>  					type = "active";
>  				};
> @@ -170,14 +177,12 @@
>  			cooling-maps {
>  				map0 {
>  					trip = <&cpu_passive>;
> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +					cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>  				};

fan == active trip point

This is referring to the passive trip point. So it should point to the
CPU as it is now. Note the order of mitigation is inverted regarding the
proposal description.

>  				map1 {
>  					trip = <&cpu_active>;
> -					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> -							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> +					cooling-device = <&fan0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
>  				};
>  
>  				map2 {
> @@ -428,6 +433,7 @@
>  	pwm: pwm@11006000 {
>  		compatible = "mediatek,mt7622-pwm";
>  		reg = <0 0x11006000 0 0x1000>;
> +		#pwm-cells = <3>;
>  		interrupts = <GIC_SPI 77 IRQ_TYPE_LEVEL_LOW>;
>  		clocks = <&topckgen CLK_TOP_PWM_SEL>,
>  			 <&pericfg CLK_PERI_PWM_PD>,
> 
> 
> regards Frank
>
Daniel Golle June 25, 2021, 10:11 a.m. UTC | #12
Hi Frank,

On Fri, Jun 25, 2021 at 11:31:59AM +0200, Frank Wunderlich wrote:
> > Gesendet: Freitag, 25. Juni 2021 um 11:22 Uhr
> > Von: "Daniel Golle" <daniel@makrotopia.org>
> 
> > On Fri, Jun 25, 2021 at 10:16:43AM +0200, Frank Wunderlich wrote:
> > > Daniel from openwrt have some other mt7622 Boards maybe he can test the Fan approach below
> >
> > I got Linksys E8450 aka. Belkin RT3200 ( https://fcc.io/K7S-03571 ) as
> > well as Ubiquiti UniFi 6 LR ( https://fcc.io/SWX-U6LR ). Both got quite
> > massive customized heatsinks (see internal photos on FCC submission),
> > which results in much better heat dissipation than just having the
> > naked chip like on the BPi-R64.
> > Hence I also can't test the fan approach on boards other than the R64.
> 
> Do your both mt7622 boards miss the fan-socket or is it not connected to pwm3? then we need to move the fan-parts to mt7622-bananapi-r64.dts instead of mt7622.dtsi

There is no fan intended on both devices.
E8450 has an unknown connector which **could** be for a fan, but I
never tried if and how it is actually connected to the SoC.
It could as well be an additional USB 2.0 (as it got 4 pins).

Hence I suggest to add the fan on PWM3 for the BPi-R64 only for now.


Cheers


Daniel
diff mbox series

Patch

diff --git a/arch/arm64/boot/dts/mediatek/mt7622.dtsi b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
index 890a942ec..b779c7aa6 100644
--- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
@@ -170,14 +170,14 @@  cpu-crit {
 			cooling-maps {
 				map0 {
 					trip = <&cpu_passive>;
-					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
-							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+					cooling-device = <&cpu0 0 0>,
+							 <&cpu1 0 0>;
 				};
 
 				map1 {
 					trip = <&cpu_active>;
-					cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
-							 <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+					cooling-device = <&cpu0 0 0>,
+							 <&cpu1 0 0>;
 				};
 
 				map2 {