V3D Drivers on RaspberryPI

It is surprising that mesa-utils package does get installed by default with Raspbian Buster, since it provides the useful diagnostic tool glxinfo

sudo apt-get install mesa-utils

It is particularly useful in determining what OpenGl renderer is in use as follows:-

glxinfo|grep render

1. Raspbian Buster PI 3B+ Legacy renderer

   direct rendering: Yes
   OpenGL renderer string: llvmpipe (LLVM 9.0.1, 128 bits)
   

2. Raspbian Buster PI 3B+ FakeKMS renderer

   direct rendering: Yes
   OpenGL renderer string: VC4 V3D 2.1
   

3. Raspbian Buster PI 3B+ FullKMS renderer

   direct rendering: Yes
   OpenGL renderer string: VC4 V3D 2.1
   

4. Raspbian Buster PI 4 Legacy renderer

   direct rendering: Yes
   OpenGL renderer string: llvmpipe (LLVM 9.0.1, 128 bits)
   

5. Raspbian Buster PI 4 FakeKMS renderer

   direct rendering: Yes
   OpenGL renderer string: V3D 4.2
   

   In my experience FakeKMS on the raspberryPI works just fine with processing P2D and P3D renderers. FullKMS on the RaspberryPI4 works fine with simpler P2D and P3D sketches. The Legacy drivers are unusable with P2D and P3D sketches.