Sonoff NSPanel Pro 120: GPU

The RK3326 chip includes a Mali-G31 GPU that supports:

• DirectX 11 (FL 9_3)
• OpenGL ES 1.1, 2.0, and 3.2
• Vulkan 1.0
• OpenCL 2.0 Full Profile

This enables efficient 3D graphics and compute capabilities for gaming, rendering, and GPGPU tasks. The RK3326 chip is widely used in one of the most popular retro gaming console R36S. It is impressive how many games this chip can handle, delivering solid performance for retro and even computer ports gaming experiences.

OpenGL was the dominant cross-platform graphics API from the 1990s through the early 2010s, widely used for desktop applications, games, and embedded systems (via OpenGL ES). The latest version, OpenGL ES 3.2, was released in 2015. Nowadays, the most widely adopted APIs are Vulkan and DirectX 12, which offer better performance and modern features.

For now, I’ve successfully managed to get OpenGL ES working, but I’m encountering some issues getting other drivers to work on ARM (Vulkan). Therefore, let’s focus on OpenGL ES for this part

OpenGL ES

The .dts is straight forward and looks like that

gpu: gpu@ff400000 {
    compatible = "rockchip,px30-mali", "arm,mali-bifrost";
    reg = <0x0 0xff400000 0x0 0x4000>;
    interrupts = <GIC_SPI 45 IRQ_TYPE_LEVEL_HIGH>,
           <GIC_SPI 46 IRQ_TYPE_LEVEL_HIGH>,
           <GIC_SPI 47 IRQ_TYPE_LEVEL_HIGH>;
    interrupt-names = "GPU", "MMU", "JOB";
    clocks = <&cru SCLK_GPU>;
    #cooling-cells = <2>;
    power-domains = <&power PX30_PD_GPU>;
    operating-points-v2 = <&gpu_opp_table>;
    upthreshold = <40>;
    downdifferential = <10>;
    mali-supply = <&vdd_logic>;
    status = "okay";
    power_model {
          compatible = "arm,mali-simple-power-model";
          static-coefficient = <411000>;
          dynamic-coefficient = <733>;
          ts = <32000 4700 (-80) 2>;
          thermal-zone = "gpu-thermal";
    };
};

Also the support for OpenGL should be included into Buildroot config (rootfs)

One of the best benchmarks for OpenGL ES is Glmark2 . Let’s run it to check the GPU functionality.

As a fun task, let’s get RetroArch running on this device. So far, we have everything set up for this, except for the sound capability. Since the sound will be up and running soon, wait for the Sonoff NSPanel to be turned into a retro game console! 😆