linux-kernel - Re: [PATCH v1] arm64: dts: qcom: ipq5424: add cooling maps for CPU thermal zones

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Message-ID: <a58956a3-b9cd-408f-98af-7ec31f2277dd@oss.qualcomm.com>
Date: Thu, 23 Oct 2025 16:26:36 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: Manikanta Mylavarapu <quic_mmanikan@...cinc.com>, andersson@...nel.org,
        konradybcio@...nel.org, robh@...nel.org, krzk+dt@...nel.org,
        conor+dt@...nel.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: quic_srichara@...cinc.com, quic_varada@...cinc.com,
        kathiravan.thirumoorthy@....qualcomm.com
Subject: Re: [PATCH v1] arm64: dts: qcom: ipq5424: add cooling maps for CPU
 thermal zones

On 10/23/25 2:21 PM, Manikanta Mylavarapu wrote:
> 
> 
> On 10/23/2025 2:09 PM, Konrad Dybcio wrote:
>> On 10/23/25 6:38 AM, Manikanta Mylavarapu wrote:
>>> Add cooling-maps to the cpu1, cpu2, and cpu3 thermal zones to associate
>>> passive trip points with CPU cooling devices. This enables proper
>>> thermal mitigation by allowing the thermal framework to throttle CPUs
>>> based on temperature thresholds. Also, label the trip points to allow
>>> referencing them in the cooling maps.
>>>
>>> Signed-off-by: Manikanta Mylavarapu <quic_mmanikan@...cinc.com>
>>> ---
>>
>> [...]
>>
>>>  		cpu1-thermal {
>>> @@ -1254,18 +1269,28 @@ cpu1-thermal {
>>>  			thermal-sensors = <&tsens 12>;
>>>  
>>>  			trips {
>>> -				cpu-critical {
>>> +				cpu1_crit: cpu-critical {
>>>  					temperature = <120000>;
>>>  					hysteresis = <9000>;
>>>  					type = "critical";
>>>  				};
>>>  
>>> -				cpu-passive {
>>> +				cpu1_alert: cpu-passive {
>>>  					temperature = <110000>;
>>>  					hysteresis = <9000>;
>>>  					type = "passive";
>>>  				};
>>
>> This means "software will start throttling the cpufreq at 110C"
>>
>> Is this what you want?
>>
> 
> Hi Konrad,
> 
> Thank you for reviewing the patch.
> 
> Yes, the intent is to initiate software-based cpufreq throttling at 110°C.
> 
>> Also, is there nothing like LMH on this platform that throttles the
>> device way earlier, without OS intervention?
>>
> 
> IPQ5424 platform does not support LMH.

Thanks for confirming

Usually it seems like the trips are ordered by temperature but I don't
think there's a strong preference

The hysteresis value is a little high, but I'm assuming that came out of
some internal tuning

Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>

Konrad