add additional protection against screen blanking

roles/kodi-config/templates/configuration.nix.j2

@@ -35,7 +35,10 @@
   services.xserver.displayManager.autoLogin.enable = true;
   services.xserver.displayManager.autoLogin.user = "kodi";
   services.xserver.displayManager.job.preStart = "/run/current-system/sw/bin/systemctl start network-online.target";
-  services.xserver.displayManager.sessionCommands = "xset s off -dpms";
+  services.xserver.displayManager.sessionCommands = ''
+    xset dpms 0 0 0
+    xset s off -dpms
+  '';
   users.users.kodi.isNormalUser = true;