Comment 38 for bug 383973

This is a very common dpms problem that was fixed just recently in the intel driver, and the regression was introduced in the "Sync DRI2 CopyRegion to vertical retrace" commit on 6/02 that snuck into karmic. If you want to test the fix, please add this PPA to your sources and pull in all of the upgrades.

https://launchpad.net/~xorg-edgers/+archive/ppa

The commits that fixed it were
http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?id=5d80e24b5fc6d6028028da6ded35389c08bfce29
and
http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?id=f0270bbb47baed78a0ff6189ae20d3ac322ec02b

The bug upstream is:
https://bugs.freedesktop.org/show_bug.cgi?id=22383