How to: Make Nvidia Optimus work after installing Ubuntu 21.04.
I own a Thinkpad T480 with a dedicated GPU (Nvidia Geforce MX 150) in addition to the onboard Intel GPU. The easiest way to have a Linux distribution with full Optimus support running would be to download the most recent PopOS! image with the proprietary Nvidia drivers baked in.
Since I cannot stand some of the modifications System76 made to Gnome I just want to get the most recent Ubuntu (or Kubuntu) version and go from there. Ubuntu installed just fine without any graphics glitched or black screens and prime-select query shows nvidia. Something was not right, however: nvidia-settings produced a tiny, empty window and judging from powertop stats it seemed like the system still used the onboard intel graphics.
After digging through ten year-old Stack Overflow posts and “solved” topics on the Nvidia forums I tried the most straightforward suggestion, which was to update to a more recent version of the Nvidia driver than what was provided through the Ubuntu install. So the whole endeavor might now be summarized as
sudo apt install nvidia-driver-470 (or whatever is newest/stable enough).Note: If you need an even newer version you might want to add the graphics-drivers/ppa repository and run sudo apt update before install.