With the X11 problems apparently solved, I discovered that the xscreensaver daemon can no longer control the screen. It just never wakes up and activates a screensaver. Trying to configure the screensaver causes the utility to complain that it cannot find the daemon and ask if I want to start it. (But note: ps -e shows that it IS running!) Trying to start it fails, with a suggestion to check $PATH and permissions. So, no screensaver.
But I use XFCE by default. Once or twice I have booted KDE instead, and one time when I left it idle long enough the screen did blank. I then poked around in the KDE system control utility and was able to set and test various screensavers. It is ONLY in XFCE that xscreensaver cannot seem to get control of the screen. (Yes, it's xscreensaver not kscreensaver. I checked.)
But I prefer to use the much lighter XFCE. What would be the difference between KDE and XFCE in how xscreensaver works? What config files could I check?
Edited by Alchemist, 12 January 2011 - 09:24 PM.