nixos/nvidia: populating /dev with nvidia devices at boot

nixos/modules/hardware/video/nvidia.nix

@@ -62,11 +62,16 @@ in
     boot.extraModulePackages = [ nvidia_x11.bin ];
 
     # nvidia-uvm is required by CUDA applications.
-    boot.kernelModules = [ "nvidia-uvm" ];
+    boot.kernelModules = [ "nvidia-uvm" ] ++
+      lib.optionals config.services.xserver.enable [ "nvidia" "nvidia_modeset" "nvidia_drm" ];
+
 
     # Create /dev/nvidia-uvm when the nvidia-uvm module is loaded.
     services.udev.extraRules =
       ''
+        KERNEL=="nvidia", RUN+="${pkgs.stdenv.shell} -c 'mknod -m 666 /dev/nvidiactl c $(grep nvidia-frontend /proc/devices | cut -d \  -f 1) 255'"
+        KERNEL=="nvidia_modeset", RUN+="${pkgs.stdenv.shell} -c 'mknod -m 666 /dev/nvidia-modeset c $(grep nvidia-frontend /proc/devices | cut -d \  -f 1) 254'"
+        KERNEL=="card*", SUBSYSTEM=="drm", DRIVERS=="nvidia", RUN+="${pkgs.stdenv.shell} -c 'mknod -m 666 /dev/nvidia%n c $(grep nvidia-frontend /proc/devices | cut -d \  -f 1) %n'"
         KERNEL=="nvidia_uvm", RUN+="${pkgs.stdenv.shell} -c 'mknod -m 666 /dev/nvidia-uvm c $(grep nvidia-uvm /proc/devices | cut -d \  -f 1) 0'"
       '';