diff --git a/util/topgen.py b/util/topgen.py
index 7ec5fd0..e5a36fc 100755
--- a/util/topgen.py
+++ b/util/topgen.py
@@ -978,7 +978,8 @@
 
     # Don't print warnings when querying the list of blocks.
     log_level = (log.ERROR if args.get_blocks else
-                 log.DEBUG if args.verbose else log.NOTSET)
+                 log.DEBUG if args.verbose else None)
+
     log.basicConfig(format="%(levelname)s: %(message)s", level=log_level)
 
     if not args.outdir: