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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170625171921.sijfwgnuk5cwdi74@kozik-lap>
Date:   Sun, 25 Jun 2017 19:19:21 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Anand Moon <linux.amoon@...il.com>
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

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?

Best regards,
Krzysztof