furthre config on laptop

system/gpu/nvidia/default.nix

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+{ lib, ... }:
+
+{
+  imports = [];
+  services.xserver.videoDrivers = lib.mkDefault [ "modesetting" "nvidia"];
+}

system/gpu/nvidia/disable.nix

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+{ ... }:
+
+{
+  # This runs only intel/amdgpu igpus and nvidia dgpus do not drain power.
+
+  ##### disable nvidia, very nice battery life.
+  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"
+  ];
+}

system/gpu/nvidia/prime.nix

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+{ lib, config, ... }:
+
+{
+  imports = [ ./. ];
+
+  options = {
+    hardware.nvidia.primeBatterySaverSpecialisation = lib.mkEnableOption "configure a specialisation which turns on NVIDIA Prime battery saver";
+  };
+
+  config = {
+
+    hardware.nvidia.prime = {
+      offload = {
+        enable = lib.mkOverride 990 true;
+        enableOffloadCmd = lib.mkIf config.hardware.nvidia.prime.offload.enable true; # Provides `nvidia-offload` command.
+      };
+      # Hardware should specify the bus ID for intel/nvidia devices
+    };
+
+    specialisation = lib.mkIf config.hardware.nvidia.primeBatterySaverSpecialisation {
+      battery-saver.configuration = {
+        system.nixos.tags = [ "battery-saver" ];
+        imports = [
+          # Leave only the integrated GPU enabled
+          ./disable.nix
+        ];
+        hardware.nvidia = {
+          prime.offload.enable = lib.mkForce false;
+          powerManagement = {
+            enable = lib.mkForce false;
+            finegrained = lib.mkForce false;
+          };
+        };
+      };
+    };
+  };
+}

system/gpu/nvidia/turing/default.nix

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+{ lib, config, ... }:
+let
+  nvidiaPackage = config.hardware.nvidia.package;
+in
+{
+  imports = [ ../. ];
+
+  # enable the open source drivers if the package supports it
+  hardware.nvidia.open = lib.mkOverride 990 (nvidiaPackage ? open && nvidiaPackage ? firmware);
+}