Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <17f3fd40-70c1-2e8d-8002-dfe9690aed88@linaro.org>
Date:   Tue, 4 Oct 2022 12:47:30 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.11.0
Subject: Re: [PATCH v3] arm64: dts: mediatek: mt8183: disable thermal zones
 without trips.
Content-Language: en-US
To:     Amjad Ouled-Ameur <aouledameur@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>
Cc:     linux-mediatek@lists.infradead.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20221004101130.17256-1-aouledameur@baylibre.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <20221004101130.17256-1-aouledameur@baylibre.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


Hi Amjad,

On 04/10/2022 12:11, Amjad Ouled-Ameur wrote:
> Thermal zones without trip point are not registered by thermal core.
> 
> tzts1 ~ tzts6 zones of mt8183 were intially introduced for test-purpose
> only.
> 
> Disable the zones above and keep only cpu_thermal enabled.

It does not make sense to disable the thermal zones. Either the thermal 
zones are needed or they are not. Keeping them for debug purpose is not 
desired.

Alternatively to removal, you can:

  - remove 'sustainable-power'
  - add a passive trip point, optionally a hot trip point and a critical 
trip point

The passive trip point will allow the userspace to set a value in order 
to get notified about the devices temperature (writable trip point). 
The hot temperature will send a notification to userspace so it can take 
a last chance decision to drop the temperature before the critical 
temperature.

The passive trip point temperature could be a high temperature.

The mitigation is also managed from userspace as a whole.


> Signed-off-by: Amjad Ouled-Ameur <aouledameur@baylibre.com>
> ---
>   arch/arm64/boot/dts/mediatek/mt8183.dtsi | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/mediatek/mt8183.dtsi b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> index 9d32871973a2..53f7a0fbaa88 100644
> --- a/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> +++ b/arch/arm64/boot/dts/mediatek/mt8183.dtsi
> @@ -1191,6 +1191,7 @@ tzts1: tzts1 {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 1>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};
> @@ -1200,6 +1201,7 @@ tzts2: tzts2 {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 2>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};
> @@ -1209,6 +1211,7 @@ tzts3: tzts3 {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 3>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};
> @@ -1218,6 +1221,7 @@ tzts4: tzts4 {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 4>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};
> @@ -1227,6 +1231,7 @@ tzts5: tzts5 {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 5>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};
> @@ -1236,6 +1241,7 @@ tztsABB: tztsABB {
>   				polling-delay = <0>;
>   				thermal-sensors = <&thermal 6>;
>   				sustainable-power = <5000>;
> +				status = "disabled";
>   				trips {};
>   				cooling-maps {};
>   			};


-- 
<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