I have an Lenovo L412 notebook with Display Port connection to the NEC EA231WMi LCD Monitor with the 1920x1080 resolution.
Then display goes to power save (configured on notebook), it doesn't goes back after user activity cause wake up. Monitor goes from power save, senses some activity on DP, and flickers sometimes, but no image displayed.
The reconnection of DP connector solves the issue. With the previous driver version (126.96.36.1995) reconnection didn't help.
The information on system and GMA configuration follows: