The RK3399 Overclock/Undervolt/Voltages Thread

[generaleramon]

hey, i'm tweaking the SoC voltages in the .dtsi files and i was wondering what was the lowest possible voltage that i could set for the CPU and/or GPU. Looking in the rk3399-pinebook-pro.dts i've found something that might help.

Code:

vdd_cpu_l: DCDC_REG2 { regulator-name = "vdd_cpu_l";          <<< cpu_l is the little cluster regulator-always-on; regulator-boot-on; regulator-min-microvolt = <750000>;    <<<750 mv regulator-max-microvolt = <1350000>;   <<<1350mv    regulator-ramp-delay = <6001>; vdd_cpu_b: regulator@40 { compatible = "silergy,syr827"; reg = <0x40>; fcs,suspend-voltage-selector = <1>; pinctrl-names = "default"; pinctrl-0 = <&vsel1_pin>; regulator-name = "vdd_cpu_b";          <<<cpu_b is the big cluster regulator-always-on; regulator-boot-on; regulator-min-microvolt = <712500>;    <<<712.5 mv regulator-max-microvolt = <1500000>;   <<<1500mv regulator-ramp-delay = <1000>; vin-supply = <&vcc_1v8>; vdd_gpu: regulator@41 { compatible = "silergy,syr828"; reg = <0x41>; fcs,suspend-voltage-selector = <1>; pinctrl-names = "default"; pinctrl-0 = <&vsel2_pin>; regulator-name = "vdd_gpu";           <<<GPU regulator-always-on; regulator-boot-on; regulator-min-microvolt = <712500>;   <<<712.5mv regulator-max-microvolt = <1500000>;  <<<1500mv regulator-ramp-delay = <1000>; vin-supply = <&vcc_1v8>;

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As of now i've found that the GPU can run at 712.5mv@400Mhz no problem but i need 775mv@500Mhz so i can confirm that it can go below the stock 800mv.
Same with the 2 cpu clusters, in some cases i was able to undervolt around 200mv at the same frequency.
i'm currently running 4xA53@1.7Ghz/2xA72@2.1Ghz/GPU@1050Mhz.
    << my (old) voltage curve

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I wonder is someone can confirm that 750-712mv is the lowest voltage that can be set and i also wonder what is the "step size", meaning how precisely i can tune it. 6.25mv like in modern gpus? 12.5? 25mv?

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EDIT: I'm pretty sure that a 12.5mv step is accepted. The A72 Cluster is stable @1Ghz with 775mv, can't even boot with 750mv, Linpack unstable with 762.5mv.

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EDIT2: 08/06/2021 - Here is my latest 99% stable rk3399-opp.dtsi file:

Code:

cluster0_opp: opp-table0 { compatible = "operating-points-v2"; opp-shared; opp00 { opp-hz = /bits/ 64 <600000000>; opp-microvolt = <750000>; clock-latency-ns = <40000>; }; opp01 { opp-hz = /bits/ 64 <696000000>; opp-microvolt = <750000>; }; opp02 { opp-hz = /bits/ 64 <816000000>; opp-microvolt = <800000>; }; opp03 { opp-hz = /bits/ 64 <1008000000>; opp-microvolt = <850000>; }; opp04 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <925000>; }; opp05 { opp-hz = /bits/ 64 <1416000000>; opp-microvolt = <1025000>; }; opp06 { opp-hz = /bits/ 64 <1512000000>; opp-microvolt = <1075000>; }; opp07 { opp-hz = /bits/ 64 <1608000000>; opp-microvolt = <1125000>; }; opp08 { opp-hz = /bits/ 64 <1704000000>; opp-microvolt = <1225000>; }; }; cluster1_opp: opp-table1 { compatible = "operating-points-v2"; opp-shared; opp00 { opp-hz = /bits/ 64 <408000000>; opp-microvolt = <725000>; clock-latency-ns = <40000>; }; opp01 { opp-hz = /bits/ 64 <600000000>; opp-microvolt = <750000>; }; opp02 { opp-hz = /bits/ 64 <696000000>; opp-microvolt = <775000>; }; opp03 { opp-hz = /bits/ 64 <816000000>; opp-microvolt = <775000>; }; opp04 { opp-hz = /bits/ 64 <1008000000>; opp-microvolt = <800000>; }; opp05 { opp-hz = /bits/ 64 <1200000000>; opp-microvolt = <850000>; }; opp06 { opp-hz = /bits/ 64 <1416000000>; opp-microvolt = <950000>; }; opp07 { opp-hz = /bits/ 64 <1512000000>; opp-microvolt = <975000>; }; opp08 { opp-hz = /bits/ 64 <1608000000>; opp-microvolt = <1025000>; }; opp09 { opp-hz = /bits/ 64 <1704000000>; opp-microvolt = <1075000>; }; opp10 { opp-hz = /bits/ 64 <1800000000>; opp-microvolt = <1125000>; }; opp11 { opp-hz = /bits/ 64 <2016000000>; opp-microvolt = <1212500>; }; opp12 { opp-hz = /bits/ 64 <2040000000>; opp-microvolt = <1225000>; }; opp13 { opp-hz = /bits/ 64 <2088000000>; opp-microvolt = <1250000>; }; opp14 { opp-hz = /bits/ 64 <2184000000>; opp-microvolt = <1325000>; }; opp15 { opp-hz = /bits/ 64 <2208000000>; opp-microvolt = <1362500>; }; }; gpu_opp_table: opp-table2 { compatible = "operating-points-v2"; opp00 { opp-hz = /bits/ 64 <297000000>; opp-microvolt = <712500>; }; opp01 { opp-hz = /bits/ 64 <400000000>; opp-microvolt = <725000>; }; opp02 { opp-hz = /bits/ 64 <500000000>; opp-microvolt = <787500>; }; opp03 { opp-hz = /bits/ 64 <600000000>; opp-microvolt = <850000>; }; opp04 { opp-hz = /bits/ 64 <800000000>; opp-microvolt = <1012500>; }; opp05 { opp-hz = /bits/ 64 <900000000>; opp-microvolt = <1087500>; }; opp06 { opp-hz = /bits/ 64 <1000000000>; opp-microvolt = <1212500>; }; opp07 { opp-hz = /bits/ 64 <1100000000>; opp-microvolt = <1275000>; }; }; };