linux-kernel - Re: [PATCH] ARM: dts: exynos: Exynos5422 Odroid-XU* incomplete thermal-zones definition

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Message-ID: <CANAwSgSZyhf-7BjwqoSAxBg=UDzCwEG=thpASEmZ=p=N5gpFQw@mail.gmail.com>
Date:   Sun, 25 Jun 2017 22:25:32 +0530
From:   Anand Moon <linux.amoon@...il.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     Willy Wolff <willy.mh.wolff@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Kukjin Kim <kgene@...nel.org>,
        Javier Martinez Canillas <javier@....samsung.com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: dts: exynos: Exynos5422 Odroid-XU* incomplete
 thermal-zones definition

Hi Krzysztof

On 25 June 2017 at 20:59, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> On Sun, Jun 25, 2017 at 08:48:13PM +0530, Anand Moon wrote:
>> Hi Krzystof,
>> >> 2: We should also increase the tips from 4 to 8 to support different
>> >> cluster of cpu's.
>> >
>> > There are 4 CPU thermal zones on Exynos5422. What do you want to expand?
>>
>> What I meant was to support more trip point to address below.
>> [    2.776320] exynos-tmu 100a0000.tmu: More trip points than
>> supported by this TMU.
>> [    2.782370] exynos-tmu 100a0000.tmu: 2 trip points should be
>> configured in polling mode.
>>
>
> I do not understand what you want to achieve. I added 2 trip points in
> polling mode for the CPU cooling mode. Just describe the problem and
> send the patch - it is the best way to explain one's thought...
>
>> >> 3: To avoid duplication of cooling-maps we can make tmu sensor work
>> >> differently for cluster of cpu's
>> >>       tmu_cpu0: handle pwm-fan control.
>> >>       tmu_cpu1: handle cpu[0-3] cpufreq mapping.
>> >>       tmu_cpu2: handle cpu[4-7] cpufreq mapping.
>> >
>> > I miss the point behind this. Why fan should work only when CPU4
>> > (tmu_cpu0) is heated and not CPU5-7 (rest of cpu tmu's)?
>>
>> Ok fan should work on all the thermal zone. To avoid thermal shutdown.
>>
>> But I want to avoid scaling down of all the cores of cpu to low freq
>> as cooling-maps cross the alert temperature. For below example.
>> ----
>>  map3 {
>>               trip = <&cpu1_alert3>;
>>               cooling-device = <&cpu0 0 2>;
>>  };
>>  map4 {
>>               trip = <&cpu1_alert3>;
>>               cooling-device = <&cpu4 0 2>;
>>  };
>>
>>  map5 {
>>               trip = <&cpu1_alert4>;
>>               cooling-device = <&cpu0 3 7>;
>>  };
>>  map6 {
>>              trip = <&cpu1_alert4>;
>>              cooling-device = <&cpu4 3 12>;
>>  };
>>
>> What I want to configure thermal zone as.
>>
>> cpu0_thermal: cpu0-thermal {
>>      configure cluster of cpu[0-3]
>>      {
>>         tips
>>      }
>>      cooling map
>>      {
>>          device handle cpu[0-3] with frequency scaling at particular
>> alert temperature.
>>      }
>> }
>
> cpu0_thermal is attached to tmu_cpu0 which is the temperature of CPU4
> (first big core). I do not see reason behind connecting thermal zone
> (thus temperature) of CPU4 with frequency of LITTLE cluster (CPU0-3). In
> case of busy CPU4, you will scale down CPU0-3. Does not make sense.
>

Both the cpu cluster are independent and have different cpu-freqency scaling.
that is the reason to for my changes.

>> cpu1_thermal: cpu1-thermal {
>>      configure cluster of cpu[4-7]
>>      {
>>         tips
>>      }
>>      cooling map
>>      {
>>          device handle cpu[4-7] with frequency scaling at particular
>> alert temperature.
>>      }
>> }
>>
>> We can chose to configure rest of the thermal-zone on this approach.
>> Please share your thoughts.
>
> I am sorry, I do not understand the idea, the problem nor the solution.
>
> Best regards,
> Krzysztof
>

Sorry for not able to express my self in technical terms.
my changes are based on exynos5433-tmu at this moment.
Just attaching small patch to share my point.

Best Regards
-Anand Moon

Download attachment "tmu.patch" of type "application/octet-stream" (7778 bytes)