DPMS and gdm

[Reid Rivenburgh]

I have a question about DPMS and gdm.  I added the following lines to
gdm's Init/Default script:

xset +dpms
xset dpms 15 30 45

(sleep 15; xset dpms force off)&

xset q > /tmp/xsetq.out

I'd like to turn the monitor off pretty soon after gdm starts.  The
"force off" line successfully turns off the monitor, but if I move the
mouse or hit a key after that, it seems like DPMS never kicks in.  The
screen will go black at some point, but the monitor never turns off.
I checked the contents of /tmp/xsetq.out, and it reports this:

DPMS (Energy Star):
  Standby: 15    Suspend: 30    Off: 45
  DPMS is Enabled
  Monitor is On

So it seems like it's being set properly.  Does anyone have any suggestions?

Some info:

xorg-x11-server-Xorg-1.4.99.901-18.20080401.fc9.x86_64
nv driver

(--) NV: Found NVIDIA GeForce 8600 GTS at 01 at 00:00:0
(II) NV(0): Monitor name: FCT1904N [a Planar LCD]
(II) NV(0): DPMS capabilities: StandBy Suspend Off(II) NV(0):

Thanks,
reid