[PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[xieqinick]

From: Nick Xie <nick@khadas.com>

Reduce the MCU FAN trigger temperature from
80 degree centigrade to 50 degree centigrade.

Signed-off-by: Nick Xie <nick@khadas.com>
---
 arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
index 66d67524b031..a9c34fee91f4 100644
--- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
@@ -256,7 +256,7 @@ &cecb_AO {
 &cpu_thermal {
 	trips {
 		cpu_active: cpu-active {
-			temperature = <80000>; /* millicelsius */
+			temperature = <50000>; /* millicelsius */
 			hysteresis = <2000>; /* millicelsius */
 			type = "active";
 		};
-- 
2.25.1


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Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[Neil Armstrong]

Hi Nick,

On 09/06/2021 03:28, xieqinick@gmail.com wrote:
> From: Nick Xie <nick@khadas.com>
> 
> Reduce the MCU FAN trigger temperature from
> 80 degree centigrade to 50 degree centigrade.

Can you add some more rationale to this change ?

> 
> Signed-off-by: Nick Xie <nick@khadas.com>
> ---
>  arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> index 66d67524b031..a9c34fee91f4 100644
> --- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> +++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> @@ -256,7 +256,7 @@ &cecb_AO {
>  &cpu_thermal {
>  	trips {
>  		cpu_active: cpu-active {
> -			temperature = <80000>; /* millicelsius */
> +			temperature = <50000>; /* millicelsius */
>  			hysteresis = <2000>; /* millicelsius */
>  			type = "active";
>  		};
> 

With that:
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>

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Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[Neil Armstrong]

Hi,

On 11/06/2021 08:54, Nick Xie wrote:
> Hello Neil,
> 
> The MCU FAN won't work until the temperature reach to 80 degree centigrade,
> Do you think the temperature is too high?

I think 80 is tool high, but I fear 50 is way too low, but if you think 50 is OK after you ran some tests, just add it to the commit log and it's ok for me.

Neil

> 
> Thanks.
> 
> Neil Armstrong <narmstrong@baylibre.com <mailto:narmstrong@baylibre.com>> 于2021年6月11日周五 下午2:44写道：
> 
>     Hi Nick,
> 
>     On 09/06/2021 03:28, xieqinick@gmail.com <mailto:xieqinick@gmail.com> wrote:
>     > From: Nick Xie <nick@khadas.com <mailto:nick@khadas.com>>
>     >
>     > Reduce the MCU FAN trigger temperature from
>     > 80 degree centigrade to 50 degree centigrade.
> 
>     Can you add some more rationale to this change ?
> 
>     >
>     > Signed-off-by: Nick Xie <nick@khadas.com <mailto:nick@khadas.com>>
>     > ---
>     >  arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi | 2 +-
>     >  1 file changed, 1 insertion(+), 1 deletion(-)
>     >
>     > diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
>     > index 66d67524b031..a9c34fee91f4 100644
>     > --- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
>     > +++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
>     > @@ -256,7 +256,7 @@ &cecb_AO {
>     >  &cpu_thermal {
>     >       trips {
>     >               cpu_active: cpu-active {
>     > -                     temperature = <80000>; /* millicelsius */
>     > +                     temperature = <50000>; /* millicelsius */
>     >                       hysteresis = <2000>; /* millicelsius */
>     >                       type = "active";
>     >               };
>     >
> 
>     With that:
>     Reviewed-by: Neil Armstrong <narmstrong@baylibre.com <mailto:narmstrong@baylibre.com>>
> 


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Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[Nick Xie]

Hello Neil,


Neil Armstrong <narmstrong@baylibre.com> 于2021年6月11日周五 下午3:15写道：
>
> Hi,
>
> On 11/06/2021 08:54, Nick Xie wrote:
> > Hello Neil,
> >
> > The MCU FAN won't work until the temperature reach to 80 degree centigrade,
> > Do you think the temperature is too high?
>
> I think 80 is tool high, but I fear 50 is way too low, but if you think 50 is OK after you ran some tests, just add it to the commit log and it's ok for me.

I think it is OK, we use it for a long time.

Thanks.

>
> Neil
>
> >
> > Thanks.
> >
> > Neil Armstrong <narmstrong@baylibre.com <mailto:narmstrong@baylibre.com>> 于2021年6月11日周五 下午2:44写道：
> >
> >     Hi Nick,
> >
> >     On 09/06/2021 03:28, xieqinick@gmail.com <mailto:xieqinick@gmail.com> wrote:
> >     > From: Nick Xie <nick@khadas.com <mailto:nick@khadas.com>>
> >     >
> >     > Reduce the MCU FAN trigger temperature from
> >     > 80 degree centigrade to 50 degree centigrade.
> >
> >     Can you add some more rationale to this change ?
> >
> >     >
> >     > Signed-off-by: Nick Xie <nick@khadas.com <mailto:nick@khadas.com>>
> >     > ---
> >     >  arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi | 2 +-
> >     >  1 file changed, 1 insertion(+), 1 deletion(-)
> >     >
> >     > diff --git a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> >     > index 66d67524b031..a9c34fee91f4 100644
> >     > --- a/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> >     > +++ b/arch/arm64/boot/dts/amlogic/meson-khadas-vim3.dtsi
> >     > @@ -256,7 +256,7 @@ &cecb_AO {
> >     >  &cpu_thermal {
> >     >       trips {
> >     >               cpu_active: cpu-active {
> >     > -                     temperature = <80000>; /* millicelsius */
> >     > +                     temperature = <50000>; /* millicelsius */
> >     >                       hysteresis = <2000>; /* millicelsius */
> >     >                       type = "active";
> >     >               };
> >     >
> >
> >     With that:
> >     Reviewed-by: Neil Armstrong <narmstrong@baylibre.com <mailto:narmstrong@baylibre.com>>
> >
>

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Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[Daniel Lezcano]

On 11/06/2021 09:30, Nick Xie wrote:
> Hello Neil,
> 
> 
> Neil Armstrong <narmstrong@baylibre.com> 于2021年6月11日周五 下午3:15写道：
>>
>> Hi,
>>
>> On 11/06/2021 08:54, Nick Xie wrote:
>>> Hello Neil,
>>>
>>> The MCU FAN won't work until the temperature reach to 80 degree centigrade,
>>> Do you think the temperature is too high?
>>
>> I think 80 is tool high, but I fear 50 is way too low, but if you think 50 is OK after you ran some tests, just add it to the commit log and it's ok for me.
> 
> I think it is OK, we use it for a long time.

50°C sounds like normal temperature with regular load. That means the
fan will be switched on most of the time when the board is used.

And this change may be put in regard with the other trip points in the
common DT. For instance, enable the fan when reaching 80°C but set the
passive trip point to 75°C instead of 85°C.

All that depends on the hardware characteristics and TDP which are in
the TRM normally.


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Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger temperature

[Neil Armstrong]

Hi,
On 11/06/2021 09:45, Daniel Lezcano wrote:
> On 11/06/2021 09:30, Nick Xie wrote:
>> Hello Neil,
>>
>>
>> Neil Armstrong <narmstrong@baylibre.com> 于2021年6月11日周五 下午3:15写道：
>>>
>>> Hi,
>>>
>>> On 11/06/2021 08:54, Nick Xie wrote:
>>>> Hello Neil,
>>>>
>>>> The MCU FAN won't work until the temperature reach to 80 degree centigrade,
>>>> Do you think the temperature is too high?
>>>
>>> I think 80 is tool high, but I fear 50 is way too low, but if you think 50 is OK after you ran some tests, just add it to the commit log and it's ok for me.
>>
>> I think it is OK, we use it for a long time.
> 
> 50°C sounds like normal temperature with regular load. That means the
> fan will be switched on most of the time when the board is used.
> 
> And this change may be put in regard with the other trip points in the
> common DT. For instance, enable the fan when reaching 80°C but set the
> passive trip point to 75°C instead of 85°C.
> 
> All that depends on the hardware characteristics and TDP which are in
> the TRM normally.
> 

I don't think such data exist in the datasheet or other public document, but the vendor source tree
sets:
- passive: 75°C
- hot 85°C
- critical 110°C

we set upstream:
- passive: 85°C
- hot 95°C
- critical 110°C

so maybe we should lower the passive & hot trip points, then the FAN 80°C trip point would be ok now according to Daniel's explanation.

Neil

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