Just getting around to figuring out why screensavers stopped working on my F22 and found this thread which has all the info I needed (thanks Glenn Holmer for the xscreensaver cheatsheet). I wanted to correct this piece of misinformation, for the archive:
On 04/14/15 16:28, Lukáš Tinkl wrote:
There's a good reason why they're gone mainly because... well they aren't really saving anything. Back in the days when everybody had TFT monitors, screensavers would actually prevent the physical damage from literally burning a still image into the monitor's matrix. These days with the LCD displays, they are doing exactly the opposite
My secondary display is an LG L246WP - 1920x1280 MVA panel (not too shabby) and it definitely burns if I forget to turn off the displays or a screensaver isn't running. I'll come in the next day to find emacs chrome burned into the screen (or the default KDE locker after I found that). :/ My primary (IPS) panel doesn't seem to suffer from this effect.
The good news is that vigorously exercising the LCD elements through all RGB states makes them respond again - the xscreensaver 'flurry' OpenGL screensaver does a great job of this - I can have the screen back to normal in about three hours. Not my idea - the use of flurry for this purpose was written up elsewhere. It was non-trivial to this information, though - many users might assume permanent hardware damage, especially if they can remember real phosphor burn from back in the day.
I'm not sure how the chemistry works, but I am sure that screensavers aren't obsolete on LCD panels, nor should they be considered merely-aesthetic functionality in KDE. If DPMS signalling were reliable under Linux the story might be different, but we've been waiting a couple decades for that to happen and it's still not the situation we have available to us.
-Bill