Comment 11 for bug 181405

This also makes it crash:

$ aticonfig --query-monitor
Data incomplete in file /etc/X11/xorg.conf
        Undefined Device "(null)" referenced by Screen "Default Screen".
aticonfig: Parsing the configuration file failed.
The above error messages are reported from XFree86 and may assist you in
diagnosing the problem with your configuration input file. Try use -f option
to generate a new configuration file.
$ aticonfig --query-monitor -f
Data incomplete in file /etc/X11/xorg.conf
        Undefined Device "(null)" referenced by Screen "Default Screen".
Segmentation fault (core dumped)

I have the default xorg.conf which was generated by installing fglrx.