--- check-pci-ids.py
+++ check-pci-ids.py
@@ -5,8 +5,8 @@
 
 # Check that the sorting order is preserved in pci.ids
 
-vendor_id = None
-device_id = None
+vendor_id = -1
+device_id = -1
 lineno    = 1
 
 file = open("pci.ids")