From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: ericwouds@gmail.com, Rob Herring <robh+dt@kernel.org>,
Matthias Brugger <matthias.bgg@gmail.com>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Fix mt7622.dtsi thermal cpu
Date: Mon, 21 Jun 2021 20:29:13 +0200 [thread overview]
Message-ID: <e30a2d01-a200-80cb-88d9-6aea62dd49f1@linaro.org> (raw)
In-Reply-To: <20210619121927.32699-1-ericwouds@gmail.com>
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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next prev parent reply other threads:[~2021-06-21 18:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-19 12:19 [PATCH] Fix mt7622.dtsi thermal cpu ericwouds
2021-06-21 18:29 ` Daniel Lezcano [this message]
2021-06-23 15:35 ` Eric Woudstra
2021-06-23 15:58 ` Daniel Lezcano
2021-06-23 18:43 ` Eric Woudstra
2021-06-23 20:08 ` Daniel Lezcano
2021-06-24 9:59 ` Eric Woudstra
2021-06-24 10:21 ` Daniel Lezcano
2021-06-24 13:29 ` Eric Woudstra
2021-06-25 8:16 ` Aw: " Frank Wunderlich
2021-06-25 9:22 ` Daniel Golle
2021-06-25 9:31 ` Aw: " Frank Wunderlich
2021-06-25 10:11 ` Daniel Golle
2021-06-25 9:57 ` Aw: " Daniel Lezcano
2021-06-25 11:03 ` Aw: " Frank Wunderlich
2021-06-25 11:07 ` Eric Woudstra
2021-06-25 11:47 ` Aw: " Daniel Lezcano
2021-06-25 12:28 ` Aw: " Frank Wunderlich
2021-06-25 12:50 ` Daniel Lezcano
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