I had same display issue with this closed question https://askubuntu.com/questions/79783/strange-random-display-issue, I am using notebook asus x450lcp with ubuntu 15.04, when this issue happen keyboard and mouse not working, and system seem not working (disk read led indicator does'nt show activity), cpu fan and power led still working. The only option to exit from this issue is hold the power button till pc shutdown then restart.
This the screenshot of the issue :
It's seem not OS issue, because when I activate Intel driver this issue happen once or twice a day, but when I using nvidia driver this issue almost gone, just one or twice a month. But I still hope can use the intel driver because more friendly with battery life.
My question is what exactly happen with my pc and how to eliminate this issue ?