Have this problem on two computers, one with openSuSE (previously 13.1, now tumbleweed) having a GTX970, the other running Mageia 5 having a GTX980Ti.
Connected Display is a Samsung U28D590, running with 3840x2160@60Hz connected via DisplayPort. Same display for both machines (no switch or anything in between, direct connection).
System runs normally fine, but when I turn off the display for a while and then turn it on again, the screen remains black. (Has to be off a bit longer, like a minute or more, not reproducible with only a few seconds off-time). The only way I’ve found so far to reactivate the display is to restart the X-Server so the gpu gets re-initialized. This only happens with high resolution modes. The standard text-console (tty) remains usable.
Driver used is latest version: 361.28. But also happened with all others before that support the GTX900 series.
Having to keep the display powered up fully all the time while letting the computer run a lengthy job that requires the X-Server is not a good workaround.
This was no problem before when I still had a GTX580 with a display connected via DVI. So the X-Server shouldn’t be the problem.