Re: [PATCH v14] thermal/drivers/mediatek/auxadc_thermal: expose all thermal sensors

[Daniel Lezcano <daniel.lezcano@linaro.org>]

On 19/11/2024 08:38, Hsin-Te Yuan wrote:
> On Fri, Nov 15, 2024 at 12:48 AM Daniel Lezcano
> <daniel.lezcano@linaro.org> wrote:
>>
>>
>> Hi,
>>
>> On 25/10/2024 14:05, Hsin-Te Yuan wrote:
>>> From: James Lo <james.lo@mediatek.com>
>>>
>>> Previously, the driver only supported reading the temperature from all
>>> sensors and returning the maximum value. This update adds another
>>> get_temp ops to support reading the temperature from each sensor
>>> separately.
>>>
>>> Especially, some thermal zones registered by this patch are needed by
>>> MT8183 since those thermal zones are necessary for mtk-svs driver.
>>
>> The DT for the mt8183 describes the sensor id = 0 as the CPU. On this,
>> there is a cooling device with trip points.
>>
>> The driver registers the id=0 as an aggregator for the sensors which
>> overloads the CPU thermal zone above.
>>
>> Why do you need to aggregate all the sensors to retrieve the max value ?
>>
>> They are all contributing differently to the heat and they should be
>> tied with their proper cooling device.
>>
>> I don't think the thermal configuration is correct and I suggest to fix
>> this aggregator by removing it.
>>
>>
>>
>   As far as I know the thermal design of Mediatek's board is based on
> the highest temperature of the whole board. Also, removing the
> aggregator will break all the boards using this driver.

AFAICT, it is not a thermal design but a thermal configuration.

What is the rational of using power numbers related to the CPU but 
aggregate all temperatures as an input to the governor ?

And for example, the mt8173 has 4 banks and 4 sensors per banks, so 16 
sensors. And they are all grouped together under the thermal zone 
"cpu-thermal" with the cpu cooling device.

So if the GPU is getting hot, we cool down the CPU ?


> By the way, I heard that baylibre is working on multi-sensor
> aggregation support, which can be the alternative solution for the
> aggregator in this driver, but that should be another story and is
> unrelated to this patch.

Right.


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