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

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Message-ID: <CANAwSgQoSQCoDBGd3dS=m0MtXWsbFvpa6Jp+wNEYGqJAogFQ8w@mail.gmail.com>
Date:   Sun, 25 Jun 2017 23:29:54 +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 22:49, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> On Sun, Jun 25, 2017 at 10:25:32PM +0530, Anand Moon wrote:
>> 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.
>
> Still does not make sense. Big is busy, LITTLE is doing nothing and you
> want to scale down LITTLE. No reason.
>
>>
>> >> 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.
>
> On Odroid XU3-family, all TMU interrupt-driven configureable trip points
> are configured. Why are you referring to Exynos5433?

Because both these ARCH are big.Little.

Best Regards
-Anand