mickey crams a lot of hardware into a tiny package, which requires more aggressive thermal throttling than for devices with a larger footprint. Configure the GPU thermal zone to throttle the GPU progressively at temperatures >= 60°C. Heat dissipated by the CPUs also affects the GPU temperature, hence we cap the CPU frequency to 1.4 GHz for temperatures above 65°C. Further throttling of the CPUs may be performed by the CPU thermal zone.
The configuration matches that of the downstream Chrome OS 3.14 kernel, the 'official' kernel for mickey. Signed-off-by: Matthias Kaehlcke <[email protected]> --- Changes in v2: - specify all CPUs as cooling devices - s/downstram/downstream/ in commit message Note: this patch depends on "ARM: dts: rockchip: Add #cooling-cells entry for rk3288 GPU" (https://lore.kernel.org/patchwork/patch/1075005/) --- arch/arm/boot/dts/rk3288-veyron-mickey.dts | 67 ++++++++++++++++++++++ 1 file changed, 67 insertions(+) diff --git a/arch/arm/boot/dts/rk3288-veyron-mickey.dts b/arch/arm/boot/dts/rk3288-veyron-mickey.dts index 34797abe3403..945e80801292 100644 --- a/arch/arm/boot/dts/rk3288-veyron-mickey.dts +++ b/arch/arm/boot/dts/rk3288-veyron-mickey.dts @@ -136,6 +136,73 @@ }; }; +&gpu_thermal { + /delete-node/ trips; + /delete-node/ cooling-maps; + + trips { + gpu_alert_warmish: gpu_alert_warmish { + temperature = <60000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + gpu_alert_warm: gpu_alert_warm { + temperature = <65000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + gpu_alert_hotter: gpu_alert_hotter { + temperature = <84000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + gpu_alert_very_very_hot: gpu_alert_very_very_hot { + temperature = <86000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "passive"; + }; + gpu_crit: gpu_crit { + temperature = <90000>; /* millicelsius */ + hysteresis = <2000>; /* millicelsius */ + type = "critical"; + }; + }; + + cooling-maps { + /* After 1st level throttle the GPU down to as low as 400 MHz */ + gpu_warmish_limit_gpu { + trip = <&gpu_alert_warmish>; + cooling-device = <&gpu THERMAL_NO_LIMIT 1>; + }; + + /* + * Slightly after we throttle the GPU, we'll also make sure that + * the CPU can't go faster than 1.4 GHz. Note that we won't + * throttle the CPU lower than 1.4 GHz due to GPU heat--we'll + * let the CPU do the rest itself. + */ + gpu_warm_limit_cpu { + trip = <&gpu_alert_warm>; + cooling-device = <&cpu0 4 4>, + <&cpu1 4 4>, + <&cpu2 4 4>, + <&cpu3 4 4>; + }; + + /* When hot, GPU goes down to 300 MHz */ + gpu_hotter_limit_gpu { + trip = <&gpu_alert_hotter>; + cooling-device = <&gpu 2 2>; + }; + + /* When really hot, don't let GPU go _above_ 300 MHz */ + gpu_very_very_hot_limit_gpu { + trip = <&gpu_alert_very_very_hot>; + cooling-device = <&gpu 2 THERMAL_NO_LIMIT>; + }; + }; +}; + &i2c2 { status = "disabled"; }; -- 2.21.0.1020.gf2820cf01a-goog
