anchor.diff:          '';
         };
   
  -      bbswitch = mkOption {
  -        default = true;
  -        type = types.bool;
  +      pmMethod = mkOption {
  +        default = "auto";
  +        type = types.enum [ "auto" "bbswitch" "nouveau" "switcheroo" "none" ];
           description = ''
  -          Set to true if you want to use bbswitch for power management of
  -          unused card.
  +          Set preferred power management method for unused card.
           '';
         };
   
  
positive.code:       wantedBy = [ "multi-user.target" ];
        before = [ "display-manager.service" ];
        serviceConfig = {
          ExecStart = "${bumblebee}/bin/bumblebeed --use-syslog -g ${cfg.group} --driver ${cfg.driver}";
        };
      };
    };
  
negative.code:     inherit useNvidia;
      useDisplayDevice = cfg.connectDisplay;
    };
  
    useBbswitch = cfg.pmMethod == "bbswitch";
  
    primus = pkgs.primus.override {
      inherit useNvidia;
  