Same here (current hardy, nvidia driver, external LCD Samsung XL20).
$ xset -q | grep -A1 DPMS
DPMS (Energy Star):
Standby: 0 Suspend: 0 Off: 0
DPMS is Enabled
Monitor is On
$ xset dpms 20 0 0
Then the screen blanks after 20 secs and then turns on again as the LCD searches the input signal and after a few seconds goes to standby (i.e. the LED backlight + fan are switched off).
Same here (current hardy, nvidia driver, external LCD Samsung XL20).
$ xset -q | grep -A1 DPMS
DPMS (Energy Star):
Standby: 0 Suspend: 0 Off: 0
DPMS is Enabled
Monitor is On
$ xset dpms 20 0 0
Then the screen blanks after 20 secs and then turns on again as the LCD searches the input signal and after a few seconds goes to standby (i.e. the LED backlight + fan are switched off).