Re: [PATCH v2 2/5] arm64: dts: rockchip: Add powerzones definition for rock960

[Daniel Lezcano <daniel.lezcano@linaro.org>]

Hi Rob,

On 07/12/2021 19:41, Rob Herring wrote:

[ ... ]

>>         thermal_zones: thermal-zones {
>>                 cpu_thermal: cpu-thermal {
>>                         polling-delay-passive = <100>;
>> @@ -2027,6 +2050,8 @@ gpu: gpu@ff9a0000 {
>>                 clocks = <&cru ACLK_GPU>;
>>                 #cooling-cells = <2>;
>>                 power-domains = <&power RK3399_PD_GPU>;
>> +               #powerzone-cells = <0>;
>> +               powerzone = <&PKG_PZ>;
> 
> Every CPU and the GPU are in the same powerzone. What is the point? Do
> you really have to be told that CPUs and GPU are a source of heat and
> might need to be limited?

A powerzone ==> can read power && set power limit

Every CPU is a powerzone as well as the GPU.

They are all grouped under PKG_PZ.

That means we have:

 pkg
  |-- cpu0-3
  |
  |-- cpu4-7
  |
  `-- gpu

We can read the power consumption of cpu0-3, cpu4-7 or gpu and set their
power limit.

We can read the power consumption of pkg (which is the sum of the power
consumption of cpu0-3, cpu4-7 and gpu) and I can set the power limit
which will ensure powerof(cpu0-3 + cpu4-7 + gpu) <= powerof(pkg).



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