DPMS doesn't work with KDE

[Nicolas Baradakis <nbk@sitadelle.com>]

I have a valid XF86Config-4 file with DPMS enabled, and I can turn the
monitor off when I run a window manager different from KDE.

However with KDE 3.3.1 I have set DPMS in the display settings of the
control center but it has no effect. The value I entered are here, but
the screen will never shut down.

$ xset q
[...]
DPMS (Energy Star):
  Standby: 300    Suspend: 600    Off: 900
  DPMS is Enabled
  Monitor is On
[...]

Under KDE the command "xset dpms force off" (off or whatever) will do
nothing. My monitor just sits there, as if I had never done anything.

-- 
Nicolas Baradakis