Issues while trying to set up a working xorg config

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1

Continuation of previous issue where I had issues with KDE detecting my displays. Given that optimus-manager is able to configure my other distro, I decided to mix its output and NixOS’s into a new one. I ended up getting a bootable and working state with the following config:

# Nixos prebuilt config lines above (Whatever is not explicitly specified by these lines)
Section "ServerLayout"
	Identifier "layout"
	Screen 0 "nvidia"
	Inactive "integrated"
EndSection

Section "Device"
	Identifier "nvidia"
	Driver "nvidia"
	BusID "PCI:1:0:0"
EndSection

Section "Screen"
	Identifier "nvidia"
	Device "nvidia"
	Option "AllowEmptyInitialConfiguration"
EndSection

Section "Device"
	Identifier "integrated"
	Driver "modesetting"
	BusID "PCI:6:0:0"
EndSection

Section "Screen"
	Identifier "integrated"
	Device "integrated"
EndSection

Which I can set in services.xserver.config with lib.mkForce. The issue is that I’m not sure how to nixi-fy this config, since if I do not specify the config this way, these lines here will run, adding

Section "ServerLayout"
    Identifier "layout"
    # From xserver.serverLayoutSection
    Screen 0 "Screen-nvidia[0]"
    Inactive "Device-modesetting[0]"
    # Breaking extra config from the lines above
    Screen "Screen-modesetting[0]"
    Screen "Screen-nvidia[0]"
EndSection

Will make one of a few processes kde related processes dump core on login (ie Process 1255 (.xdg-desktop-po) of user 175 dumped core.) locking me out of my desktop. I can also reproduce this by manually editing the xorg.config string to include them. Declaring them afterwards with mkAfter also doesn’t seem to work either.

Although the mkForce method does work, it hardcodes a few paths in Section "Files" along with some other config options, so it’s less than ideal. I also tried using services.xserver.drivers, but to be able to create a screen section, I still need to activate the same flag that sets the above lines, which means I’m back to square one.

2

Solved

specialisation = {
    external-display.configuration = {
      system.nixos.tags = [ "external-display" ];

      services.xserver = {
        # Genereated with arandr
        displayManager.setupCommands = lib.readFile ./layout.sh;
        videoDrivers = lib.mkForce [ "nvidia" ];
      };
      hardware.opengl.enable = true;
      hardware.nvidia = {
        powerManagement.enable = true;
        modesetting.enable = true;
        prime = {
          offload.enable = lib.mkForce false;
          sync.enable = true;

          nvidiaBusId = "PCI:1:0:0";
          amdgpuBusId = "PCI:6:0:0";
        };
      };
    };
  };