If you have xine, and the xine-gui packages installed, open a terminal, with a movie DVD in the tray of the second optical drive, and enter;
[polack@fatman ~]$ xine dvd://dev/hdx
Replace hdx with the correct designation for the second optical drive. Otherwise try;
[polack@fatman ~]$ smplayer dvd://dev/hdx
[polack@fatman ~]$ kaffeine dvd://dev/hdx
[polack@fatman ~]$ gmplayer dvd:// /dev/hdx -really-quiet
Note the space between dvd:// and /dev/hdx in the last command. All of these commands work for me, even after removing the device designations entirely from the preferences/configuration for each application.