anchor.diff:    ###### interface
   
     options = {
  -  
  +
       powerManagement.scsiLinkPolicy = mkOption {
         default = "";
         example = "min_power";
  
positive.code:         the kernel configures "max_performance".
        '';
      };
      
    };
  
  
  
negative.code:   config = mkIf (config.powerManagement.scsiLinkPolicy != "") {
  
      jobs."scsi-link-pm" =
        { description = "SCSI Link Power Management Policy";
  
          startOn = "stopped udevtrigger";
  
          task = true;
  
          script = ''
            shopt -s nullglob
            for x in /sys/class/scsi_host/host*/link_power_management_policy; do
              echo ${config.powerManagement.scsiLinkPolicy} > $x
            done
          '';
        };
  
    };
  
  }
  