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    SubjectRe: [PATCH] Fix mt7622.dtsi thermal cpu
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    On 19/06/2021 14:19, ericwouds@gmail.com wrote:
    > From: Eric Woudstra <ericwouds@gmail.com>
    >
    > Cpu-thermal is set to use all frequencies already at 47 degrees.
    > Using the CPU at 50 for a minute, the CPU has reached 48 degrees, is
    > throttled back to lowest setting, making the mt7622 terrribly slow.
    > Even at this low speed, the CPU does not cool down lower then 47 so
    > the CPU is stuck at lowest possible frequency until it shut down and
    > stays off for 15 minutes.
    >
    > cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
    > <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
    >
    > This should not be set al every cooling map. It should only be set at
    > the highest cooling map. Same as in the example:
    >
    > https://www.kernel.org/doc/Documentation/devicetree/bindings/
    > thermal/thermal.txt line 272
    >
    > But then without the fan and added a third map.
    >
    > Now temperature will be regulated at 87 degrees celcius. At temperatures
    > lower then 87, all frequencies can be used.

    47°C is really a too low temperature and this performance drop is normal.

    I would not remove the passive mitigation but try by increasing the CPU
    temp to 70°C and by changing the active trip point to 80°C. If it works
    fine, try 75°C and 85°C.

    To test, the thermal killer is dhrystone (one thread per cpu).

    With a 75°C passive trip point, the step wise thermal governor, I think
    the mitigation will happen smoothly providing better performances, and
    probably the fan won't fire.

    > Also see the post:
    >
    > http://forum.banana-pi.org/t/bpi-r64-only-10-cpu-speed-at-already-48-
    > degrees-celcius-speed-not-increasing-anymore/12262
    >
    > Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
    > ---
    > arch/arm64/boot/dts/mediatek/mt7622.dtsi | 8 ++++----
    > 1 file changed, 4 insertions(+), 4 deletions(-)
    >
    > diff --git a/arch/arm64/boot/dts/mediatek/mt7622.dtsi b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
    > index 890a942ec..b779c7aa6 100644
    > --- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
    > +++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
    > @@ -170,14 +170,14 @@ cpu-crit {
    > cooling-maps {
    > map0 {
    > trip = <&cpu_passive>;
    > - cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
    > - <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
    > + cooling-device = <&cpu0 0 0>,
    > + <&cpu1 0 0>;
    > };
    >
    > map1 {
    > trip = <&cpu_active>;
    > - cooling-device = <&cpu0 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>,
    > - <&cpu1 THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
    > + cooling-device = <&cpu0 0 0>,
    > + <&cpu1 0 0>;
    > };
    >
    > map2 {
    >


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