Comment 20 for bug 749084

Same here, I used to set screen brightness with something like

dbus-send --print-reply --dest=org.freedesktop.compiz /org/freedesktop/compiz-1/obs/screen0/brightness_values org.freedesktop.compiz.set array:int32:80

that has no effect now.
Also the examples at http://wiki.compiz.org/Plugins/Dbus have no effect or error out.

For example

$ python compiz-send.py vpswitch
Traceback (most recent call last):
  File "compiz-send.py", line 82, in <module>
    print '\n'.join(obj.list())
  File "/usr/lib/pymodules/python2.7/dbus/proxies.py", line 68, in __call__
    return self._proxy_method(*args, **keywords)
  File "/usr/lib/pymodules/python2.7/dbus/proxies.py", line 140, in __call__
    **keywords)
  File "/usr/lib/pymodules/python2.7/dbus/connection.py", line 630, in call_blocking
    message, timeout)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.UnknownMethod: Method "list" with signature "" on interface "org.freedesktop.compiz" doesn't exist