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Date:   Thu, 3 Nov 2022 17:42:28 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To:     Konrad Dybcio <konrad.dybcio@somainline.org>
Cc:     andersson@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, johan+linaro@kernel.org,
        quic_jprakash@quicinc.com, linux-arm-msm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        steev@kali.org
Subject: Re: [PATCH v2 12/12] arm64: dts: qcom: sc8280xp-x13s: Add thermal
 zone support
Message-ID: <20221103121228.GB8434@thinkpad>
References: <20221029051449.30678-1-manivannan.sadhasivam@linaro.org>
 <20221029051449.30678-13-manivannan.sadhasivam@linaro.org>
 <90b7e0e0-a354-f64d-8c53-aa80df684a3a@somainline.org>
 <20221103055014.GA8434@thinkpad>
 <e46c817b-1a3b-d20c-22e7-a67b7684f17b@somainline.org>
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On Thu, Nov 03, 2022 at 11:02:30AM +0100, Konrad Dybcio wrote:
> 
> On 03/11/2022 06:50, Manivannan Sadhasivam wrote:
> > On Sat, Oct 29, 2022 at 04:29:05PM +0200, Konrad Dybcio wrote:
> > > 
> > > On 29.10.2022 07:14, Manivannan Sadhasivam wrote:
> > > > Add thermal zone support by making use of the thermistor SYS_THERM6.
> > > > Based on experiments, this thermistor seems to reflect the actual
> > > > surface temperature of the laptop.
> > > > 
> > > > For the cooling device, all BIG CPU cores are throttle down to keep the
> > > s/throttle/throttled
> > > 
> > > Is it okay to let the 4xA78C run at full throttle in thermal emergencies though?
> > I don't get it. Can you elaborate?
> 
> 8280xp has 4xA78C and 4xX1C. You only added the latter ones to the cooling
> map.
> 

Right, that's because the first 4 cores doesn't contribute to thermal much and
thottling them doesn't yield any thermal gain.

Thanks,
Mani

> 
> > 
> > > > temperature at a sane level.
> > > > 
> > > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > > ---
> > > >   .../qcom/sc8280xp-lenovo-thinkpad-x13s.dts    | 46 +++++++++++++++++++
> > > >   1 file changed, 46 insertions(+)
> > > > 
> > > > diff --git a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > index ca77c19c6d0d..96e2fa72f782 100644
> > > > --- a/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > +++ b/arch/arm64/boot/dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts
> > > > @@ -29,6 +29,52 @@ backlight {
> > > >   		pinctrl-0 = <&edp_bl_en>, <&edp_bl_pwm>;
> > > >   	};
> > > > +	thermal-zones {
> > > > +		skin-temp-thermal {
> > > > +			polling-delay-passive = <250>;
> > > > +			polling-delay = <0>;
> > > > +			thermal-sensors = <&pmk8280_adc_tm 5>;
> > > > +
> > > > +			trips {
> > > > +				skin_temp_alert0: trip-point0 {
> > > > +					temperature = <55000>;
> > > > +					hysteresis = <1000>;
> > > > +					type = "passive";
> > > > +				};
> > > > +
> > > > +				skin_temp_alert1: trip-point1 {
> > > > +					temperature = <58000>;
> > > > +					hysteresis = <1000>;
> > > > +					type = "passive";
> > > > +				};
> > > > +
> > > > +				skin-temp-crit {
> > > > +					temperature = <73000>;
> > > Ouch, I didn't know we were serving burnt fingers at the cafeteria today :D
> > > 
> > > Or maybe this just looks scary.. The laptop looks plastic, so maybe it won't cause instant
> > > burns?
> > > 
> > 73c is what the reasonable number I came up with after some experiments. At
> > this point the temperature won't burn your finger but crossing this surely
> > would (that's what happening without this series).
> 
> Ok, then I suppose it's fine. Thanks!
> 
> 
> Konrad
> 
> > 
> > Thanks,
> > Mani
> > 
> > > Konrad
> > > > +					hysteresis = <1000>;
> > > > +					type = "critical";
> > > > +				};
> > > > +			};
> > > > +
> > > > +			cooling-maps {
> > > > +				map0 {
> > > > +					trip = <&skin_temp_alert0>;
> > > > +					cooling-device = <&CPU4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > > > +				};
> > > > +
> > > > +				map1 {
> > > > +					trip = <&skin_temp_alert1>;
> > > > +					cooling-device = <&CPU4 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU5 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU6 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
> > > > +							 <&CPU7 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
> > > > +				};
> > > > +			};
> > > > +		};
> > > > +	};
> > > > +
> > > >   	vreg_edp_bl: regulator-edp-bl {
> > > >   		compatible = "regulator-fixed";

-- 
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