Version: (using KDE 4.0.0) Installed from: Debian testing/unstable Packages When the screen is turned off using for example: /usr/bin/xset -display :0.0 dpms force off it gets turned on again after a couple of seconds and the screensaver appears. This happens only when the screensaver is enabled (start automatically after x minutes). I haven't observed whether this disables power saving features as a whole but I have witnessed the monitor being in the screensaver mode for long periods of time (longer than the 15 minutes I've specified as the switch off time). Also when you close the lid of your laptop, it effectively keeps the screen still on. I have no ideas how to debug this.
I can confirm this, on my laptop (Dell Inspiron B130, all Intel hardware) I can produce the following problems with the following procedures: 1) Enable screensaver with or without lock after time X 2) Close laptop -> LCD backlight turns off 3) After a second or so LCD backlight turns back on and screensaver is running 1) Enable screensaver to activate after X minutes 2) Enable Display Power Management to do *anything* after X+1 minutes 3) Display remains on with screensaver running, i.e. Display Power Management Settings have no effect. I can reproduce this under KDE 4.1.3 on Debian Lenny with KDE4 backport (http://kde4.debian.net) and also under KDE 4.1.2 on Slackware-current. I think perhaps Bug 156605 , Bug 165265 , Bug 170478 , and Bug 165368 all relate back to the same DPMS+screensaver=no_worky issue.
*** This bug has been marked as a duplicate of bug 165265 ***