Traceback (most recent call last):
  File "/usr/sbin/oem-config-dm", line 129, in <module>
    sys.exit(dm.run(*sys.argv[3:]))
  File "/usr/sbin/oem-config-dm", line 74, in run
    (root_width, root_height) = root.get_size()
AttributeError: 'NoneType' object has no attribute 'get_size'