linux-kernel - Re: [PATCH v14] thermal/drivers/mediatek/auxadc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <cfca677b-bc74-49bb-a031-6f52629edd2b@linaro.org>
Date: Tue, 19 Nov 2024 22:40:45 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Hsin-Te Yuan <yuanhsinte@...omium.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
 Lukasz Luba <lukasz.luba@....com>, Matthias Brugger
 <matthias.bgg@...il.com>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
 linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org,
 James Lo <james.lo@...iatek.com>, Michael Kao <michael.kao@...iatek.com>,
 Hsin-Yi Wang <hsinyi@...omium.org>, Ben Tseng <ben.tseng@...iatek.com>
Subject: Re: [PATCH v14] thermal/drivers/mediatek/auxadc_thermal: expose all
 thermal sensors

On 19/11/2024 08:38, Hsin-Te Yuan wrote:
> On Fri, Nov 15, 2024 at 12:48 AM Daniel Lezcano
> <daniel.lezcano@...aro.org> wrote:
>>
>>
>> Hi,
>>
>> On 25/10/2024 14:05, Hsin-Te Yuan wrote:
>>> From: James Lo <james.lo@...iatek.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.

-- 
<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