anchor.diff:        modules = [ nvidia_x11.bin ];
         deviceSection = optionalString syncCfg.enable
           ''
  -          BusID "${syncCfg.nvidiaBusId}"
  +          BusID "${pCfg.nvidiaBusId}"
             ${optionalString syncCfg.allowExternalGpu "Option \"AllowExternalGpus\""}
           '';
         screenSection =
  
positive.code:       '';
      };
  
      hardware.nvidia.prime.sync.enable = mkOption {
        type = types.bool;
        default = false;
  
negative.code: 
        {
          assertion = !syncCfg.enable ||
            (pCfg.nvidiaBusId != "" && pCfg.intelBusId != "");
          message = ''
            When NVIDIA Optimus via PRIME is enabled, the GPU bus IDs must configured.
          '';
  