Comment 28 for bug 447728

I've been having a similar issue in Debian Squeeze on my desktop PC. I think I just found a workaround not involving looping "xset dpms force off" every 2 seconds. I also think it's a problem with xorg; or perhaps more likely in my case, a problem between my chair and keyboard.

I have an older NVidia video chipset and run the 173xx legacy non-free driver. I have a Wacom Graphire tablet for a pointing device. I installed Debian Squeeze without a GUI, then installed Xfce. I do not have gnome-power-manager installed. Executing "xset dpms force off" has been resulting in my monitor going into standby for a couple of seconds, then turning itself back on -- even if I take the mouse off the tablet and set it harmlessly aside.

I worked around it by commenting out some unnecessary things in xorg.conf. Now executing "xset dpms force off" successfully puts my monitor into standby, as does Xscreensaver.

To do this, I commented out the Screen line in Section "ServerLayout", as well as Section "Screen" and Section "Monitor" in their entirety. Apparently xorg detects its running environment better at runtime than it did with X -configure. If I didn't have this Wacom tablet, I'm sure I'd be fine with just the Section "Module" and Section "Device" sections, and nothing else. If I didn't care about glx either, I wouldn't need an xorg.conf at all.

For what it's worth, when I first installed Squeeze, I had two video cards. My second was an old Riva128. Try as I might for several hours, I could get neither TwinView nor Xinerama to pick up my second display with any combination of drivers, so I eventually just yanked the ancient thrift store card. Now here's the interesting part: I just realized that my Screen line in section "ServerLayout" was (I'm guessing) still written as though Screen0 were one of a pair of displays. It has read as follows:

        Screen 0 "Screen0" 0 0

This leads me to ask, could it be that this 2-second dpms problem is affecting machines with un- or mis-configured multiple displays? Laptops have an external display as well as the built-in screen, after all. I didn't bother Googling all the brands / models in this thread, but it seems to me that at least the majority are laptops. Therefore, they probably all have a secondary display.

This suggests that a better workaround for some people might be to disable the VGA port in the laptop's BIOS and / or trimming some fat in xorg.conf. I'll leave the research for my hypothesis to anyone who is still having the problem.