Graphics can be rendered using the linux framebuffer device, /dev/fb0. By default the framebuffer is 800×480 with a B8G8R8A8 pixel order.

The framebuffer driver implements some special ioctls, its source is available here. Some notable ones:

• MXCFB_WAIT_FOR_VSYNC (_IOW('F', 0x20, u_int32_t)) blocks until vblank. The argument is ignored.
• MXCFB_SET_GPU_SPLIT_FMT (_IOW('F', 0x2F, struct mxcfb_gpu_split_fmt)) seems to be used to setup triple-buffering (but how to use it properly?)