fatteh: enable cuda

systems/fatteh/configuration.nix

@@ -5,6 +5,7 @@
 }:
 {
   imports = [
+    ./cuda.nix
     ./hardware-configuration.nix
     ../../configs/networkmanager.nix
     ../../configs/default.nix

systems/fatteh/cuda.nix

@@ -0,0 +1,42 @@
+{
+  nixpkgs.config = {
+    allowUnfree = true;
+  };
+  services.xserver.videoDrivers = [ "nvidia" ];
+
+  hardware.nvidia = {
+    modesetting.enable = true; # needed for PRIME
+    open = false; # MX150 (Pascal) needs proprietary firmware
+    nvidiaSettings = true;
+    prime = {
+      offload = {
+        enable = true;
+        enableOffloadCmd = true;
+      };
+      # from lspci
+      intelBusId = "PCI:0:2:0"; # Intel UHD Graphics 620
+      nvidiaBusId = "PCI:1:0:0"; # NVIDIA GeForce MX150
+    };
+  };
+
+  nix.settings.system-features = [ "cuda" ];
+
+  programs.nix-required-mounts = {
+    enable = true;
+    presets.nvidia-gpu.enable = true;
+    # Workaround for <https://github.com/NixOS/nix/issues/9272>, copied from
+    # <https://github.com/nix-community/infra/pull/1807>.
+    extraWrapperArgs = [
+      "--run shift"
+      "--add-flag '${
+        builtins.unsafeDiscardOutputDependency
+          (derivation {
+            name = "needs-cuda";
+            builder = "_";
+            system = "_";
+            requiredSystemFeatures = [ "cuda" ];
+          }).drvPath
+      }'"
+    ];
+  };
+}