Written by kchoix the 12 Oct 12 at 00:51.
Related project: Xubuntu.
Under Screensaver->Advanced[tab]->Display Power Management.
If quick power-off in blank only mode is checked, then it makes more sense to also power-off the monitor in situation where: in a locked state and password timer expires.
This makes ubuntu appear more congruent with settings and becomes more laptop battery friendly since monitor will be kept off after timer expires.
wrote on the 19 Oct 12 at 13:21
Running 'xset dpms' commands upon screensaver start/stop seems more appropriate for a Forums or AskUbuntu question. This seems like a support request - the software already exists, you're just asking how to put it together.
The next step, adding the answer and a GUI checkbox, is certainly within the capability of many Ubuntu community members. Either the appropriate patches can go to the Screensaver package maintainers, or it can be packaged separately.