Is xscreensaver the culprit? Bugs reported here are similiar, but not exact the same
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=891578 https://dirkmittler.homeip.net/blog/archives/5226 deinstalled xscreensaver, just resumed from black screen and had neither slow firefox nor x-crashes after openOffice-restore. will watch and report Wolfgang --