Noticed this comment that exactly describes the problem, so I'd say the fix is known, and probably available upstream. Note: setting memoryLimit=0 in ~/.xscreensaver as they suggest does not fix the problem.
From: /usr/share/doc/xscreensaver-gl/README.gl "If you are having problems with running the GL screenhacs from xscreensaver, but not from a window, please see <http://www.jwz.org/xscreensaver/faq.html#gl-mem>, especially if you are using nVIdia's GL implementation. This has appeared as a SIGSEGV crash and as a failutre to allocate GL context. In particular: 1.I upgraded to 3.33, and xscreensaver won't run GL hacks any more (or they run slowly), but they work fine from the command line. Try editing your .xscreensaver file and changing the memoryLimit setting to 0. Version 3.33 introduced the memoryLimit option as a precautionary limit to prevent runaway memory use if one of the display modes happened to be buggy; it prevents any program launched by xscreensaver from allocating more than that much memory. It defaults to 50M, which is a lot. However, apparently certain OpenGL libraries (notably nVidia) do something strange that makes them appear to allocate more than 128M of memory for every OpenGL program! Consequently, those programs die on startup because they aren't able to allocate memory. On some systems, memoryLimit doesn't cause the GL programs to crash, but instead, causes them to run slowly (non-accelerated.) Turning off the memory limit should work around this." -- rss-glx really slow (only 1-2fps) since recent fglrx driver update https://launchpad.net/bugs/51576 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs