Ubuntu - GPU - LLVMpipe

LLVMpipe is a Gallium3D graphics driver in Mesa that does all rendering on the CPU for providing a software-accelerated fallback on Linux and can also be used in OpenGL / graphics driver debugging.

LLVMpipe uses LLVM for providing better performance than the Softpipe driver.

WARNING: LLVMpipe is Software driven, and not Hardware driver.

So it may be very slow.

Force use of LLVMpipe