Originally Posted by danix
I'm assuming that this isn't specific to having two montors: i.e., with just a single monitor on the DP->DVI dongle (please let us know the make and model of this dongle, if possible) the same symptom is observed when entering DPMS.
Yes, same thing happens just a single monitor on DP->DVI. I'll try to find out which model the dongle is.
The attached bug report is with just a single monitor connected, and after a DPMS off/on cycle.