This affects me too. I have a GTX 660 connected to a HP LP2475w monitor with Ubuntu Desktop 14.04 over a DisplayPort cable. Switch the monitor off and on again, and it says no signal. I have to reboot to get the machine back. This makes DisplayPort unusable. The problem goes away with a DVI cable. See my question here:
This affects me too. I have a GTX 660 connected to a HP LP2475w monitor with Ubuntu Desktop 14.04 over a DisplayPort cable. Switch the monitor off and on again, and it says no signal. I have to reboot to get the machine back. This makes DisplayPort unusable. The problem goes away with a DVI cable. See my question here:
http:// askubuntu. com/questions/ 546818/ displayport- monitor- not-detected- if-switched- off-and- on-again