Re: [PATCH v2] arm64: dts: mediatek: mt8192: Add missing trip point in thermal zone

From: Hsin-Te Yuan
Date: Wed Apr 10 2024 - 08:07:20 EST

Hi Angelo,

1. 68°C is provided by MediaTek previously in downstream
2. I think sustainable power will be estimated by
estimate_sustainable_power in drivers/thermal/gov_power_allocator.c,
but I'll ask MediaTek if they can provide the precise value.
3. Sure. I'll do it in v3 after I check 2. with MediaTek

Regards,
Hsin-Te

On Wed, Apr 10, 2024 at 5:50 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
>
> Il 10/04/24 10:40, Hsin-Te Yuan ha scritto:
> > According to Documentation/driver-api/thermal/power_allocator.rst, there
> > should be two passive trip points. Adding the missing trip point to
> > ensure that the governor works optimally.
> >
> > Fixes: c7a728051f4e ("arm64: dts: mediatek: mt8192: Add thermal nodes and thermal zones")
> > Signed-off-by: Hsin-Te Yuan <yuanhsinte@xxxxxxxxxxxx>
>
> That's better - but while I can agree about setting a general temperature
> for that, I still have a few questions and requests:
>
> 1. Why is this 68°C? Was that value provided by MediaTek, or was it calculated?
> 1b. If this was calculated, please, can you explain how?
>
> 2. The power allocator documentation also says that the governor works good
> when a "sustainable dissipatable power" parameter is fed to it through the
> `sustainable-power` devicetree property (with that being strictly board
> specific and never SoC-global, as that depends on the form factor and on
> the cooling method of the machine), can you please also add the right
> sustainable power indication to the Chromebook devicetrees?
> In the MT8192 specific case, that's mt8192-asurada.dtsi.
>
> 3. I just noticed that MT8192 is not the only one that would be affected by
> the issue that you're describing in this commit; can you please perform a
> similar change on the others, if parameters are known?
>
> Thanks,
> Angelo
>
> > ---
> > Changes in v2:
> > - Clearify the reason of adding another passive trip point
> > - Link to v1: https://lore.kernel.org/r/20240410-upstream-torvalds-master-v1-1-852e903f0cec@xxxxxxxxxxxx
> > ---
> > arch/arm64/boot/dts/mediatek/mt8192.dtsi | 40 ++++++++++++++++++++++++++++++++
> > 1 file changed, 40 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/mediatek/mt8192.dtsi b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > index 05e401670bced..08d8bccc84669 100644
> > --- a/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > +++ b/arch/arm64/boot/dts/mediatek/mt8192.dtsi
> > @@ -1959,6 +1959,11 @@ cpu0-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_LITTLE_CPU0>;
> >
> > trips {
> > + cpu0_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu0_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -1989,6 +1994,11 @@ cpu1-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_LITTLE_CPU1>;
> >
> > trips {
> > + cpu1_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu1_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2019,6 +2029,11 @@ cpu2-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_LITTLE_CPU2>;
> >
> > trips {
> > + cpu2_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu2_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2049,6 +2064,11 @@ cpu3-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_LITTLE_CPU3>;
> >
> > trips {
> > + cpu3_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu3_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2079,6 +2099,11 @@ cpu4-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_BIG_CPU0>;
> >
> > trips {
> > + cpu4_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu4_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2109,6 +2134,11 @@ cpu5-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_BIG_CPU1>;
> >
> > trips {
> > + cpu5_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu5_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2139,6 +2169,11 @@ cpu6-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_BIG_CPU2>;
> >
> > trips {
> > + cpu6_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu6_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> > @@ -2169,6 +2204,11 @@ cpu7-thermal {
> > thermal-sensors = <&lvts_mcu MT8192_MCU_BIG_CPU3>;
> >
> > trips {
> > + cpu7_thres: trip-point {
> > + temperature = <68000>;
> > + hysteresis = <2000>;
> > + type = "passive";
> > + };
> > cpu7_alert: trip-alert {
> > temperature = <85000>;
> > hysteresis = <2000>;
> >
> > ---
> > base-commit: 20cb38a7af88dc40095da7c2c9094da3873fea23
> > change-id: 20240410-upstream-torvalds-master-40aeff5416c7
> >
> > Best regards,
>
>