Completely turning of nvidia dGPU on laptops with nvidia optimus

Guides
1

Just wanted to share something that may make someones life a bit easier
The unofficial wiki tells you to add the following to turn off the dGPU (see here)

boot.extraModprobeConfig = ''
  blacklist nouveau
  options nouveau modeset=0
'';
services.udev.extraRules = ''
  # Remove NVIDIA USB xHCI Host Controller devices, if present
  ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x0c0330", ATTR{power/control}="auto", ATTR{remove}="1"
  # Remove NVIDIA USB Type-C UCSI devices, if present
  ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x0c8000", ATTR{power/control}="auto", ATTR{remove}="1"
  # Remove NVIDIA Audio devices, if present
  ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x040300", ATTR{power/control}="auto", ATTR{remove}="1"
  # Remove NVIDIA VGA/3D controller devices
  ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x03[0-9]*", ATTR{power/control}="auto", ATTR{remove}="1"
'';
boot.blacklistedKernelModules = [ "nouveau" "nvidia" "nvidia_drm" "nvidia_modeset" ];

but this did not work for me ( xorg would crash upon login and return me back to gdm)
i also had to add the following line to make it work

services.xserver.videoDrivers = ["nvidia" "modesetting"];

Specializations can also be used to make switching easy! Heres my config

  specialisation = {
    on-the-go.configuration = {
      system.nixos.tags = ["on-the-go"];
      hardware.nvidia = {
        prime.offload.enable = lib.mkForce true;
        prime.offload.enableOffloadCmd = lib.mkForce true;
        prime.sync.enable = lib.mkForce false;
      };
    };
    battery-saver.configuration = {
      system.nixos.tags = ["battery-saver"];

      services.xserver.videoDrivers = lib.mkForce ["nvidia" "modesetting"];
      boot.extraModprobeConfig = ''
        blacklist nouveau
        options nouveau modeset=0
      '';

      services.udev.extraRules = ''
        # Remove NVIDIA USB xHCI Host Controller devices, if present
        ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x0c0330", ATTR{power/control}="auto", ATTR{remove}="1"
        # Remove NVIDIA USB Type-C UCSI devices, if present
        ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x0c8000", ATTR{power/control}="auto", ATTR{remove}="1"
        # Remove NVIDIA Audio devices, if present
        ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x040300", ATTR{power/control}="auto", ATTR{remove}="1"
        # Remove NVIDIA VGA/3D controller devices
        ACTION=="add", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x03[0-9]*", ATTR{power/control}="auto", ATTR{remove}="1"
      '';
      boot.blacklistedKernelModules = ["nouveau" "nvidia" "nvidia_drm" "nvidia_modeset"];

      systemd.services.nbfc_service.enable = lib.mkForce false;
    };
  };

Full config file for nvidia can be seen here

1 Like
2

I wonder whether it’s worth making a NixOS option for this… I want to say “probably” without looking at the details. One detail that I would look at is what related options already exist.

3

There seems to already be one , although it dosent work for me (i cant login to i3wm even with modsetting drivers)
hardware.nvidiaOptimus.disable (see here)
Although I’m not sure why this is under nvidiaOptimus and not nvidia.prime

4

Hey, I don’t have such hardware. If you want to pursue this, I suggest trying your best to answer your own questions and then when you (as I often do miserably) fail, ask in the development category.

By the way, I wonder whether you’d be interested in looking into

I know it’s on my list!

5

If you want to pursue this, I suggest trying your best to answer your own questions and then when you (as I often do miserably) fail, ask in the development category.

:sweat_smile:

nix-facter seems cool! I’ll check it out