Binary package hint: xscreensaver
The so-called planetary gears screensaver comes from the presence of /usr/share/applications/screensavers/planetary_gears.desktop, which is provided by the xscreensaver-gl package. The configuration is:
[Desktop Entry]
Encoding=UTF-8
Name=Planetary Gears
Comment=This draws sets of turning, interlocking gears, rotating in three dimensions. Another GL hack, by Danny Sung, Brian Paul, Ed Mackey, and Jamie Zawinski.
TryExec=gears
Exec=gears -planetary -root
StartupNotify=false
Terminal=false
Type=Application
Categories=Screensaver
X-Ubuntu-Gettext-Domain=xscreensaver
As you can see, this really executes the gears screensaver (which otherwise works fine), passing -planetary and -root as parameters. The gears screensaver doesn't understand -planetary, as you can see from:
# ./gears -planetary -root
Gears: from the XScreenSaver 5.04 distribution (13-Nov-2007.)
http://www.jwz.org/xscreensaver/
Unrecognised option: -planetary
Options include: -root, -window, -mono, -install, -noinstall,
-visual <arg>, -window-id <arg>, -pair, -spin, -no-spin,
-speed <arg>, -wander, -no-wander, -count <arg>,
-delay <arg>, -wireframe, -no-wireframe, -fps, -no-fps.
This results in a blank screen instead of the screensaver. I have looked at the gears source code, and it no longer supports that option, therefore the planetary_gears.desktop file should be dropped (unless someone wants to change the gears code).
This bug has bitten me on new installs. I also wish xscreensaver would default to a simple screen saver (such as Deco). I can't count the number of times a machine has frozen on a new install when it goes to a random 3D screensaver and the graphics card was not set up properly. This results in what appears to be a hard lockup for a new user. And this results in more posts to the forums. Let the user explore the screen savers on his own time. Using Random as the default adds to problems at a time when the user base is growing.
Excellent bug description by Bergman.