Comment 9 for bug 1533675

I had the same on issue on my Lenovo T450 running Oracle Linux 7.2

xorg-x11-server-utils-7.7-14.el7.x86_64
xorg-x11-server-common-1.17.2-10.el7.x86_64
xorg-x11-server-Xorg-1.17.2-10.el7.x86_64
xorg-x11-drv-intel-2.99.917-8.20150615.el7.x86_64
kernel-uek-4.1.12-32.2.3.el7uek.x86_64

After reading this post

https://www.reddit.com/r/archlinux/comments/4cojj9/it_is_probably_time_to_ditch_xf86videointel/

I've tried using modesetting instead of Intel x11 driver

Section "Device"
   Identifier "Intel Graphics"
   Driver "modesetting"
EndSection

and the issue is gone.

I'm running GNOME-3.14: I don't know if Unity is able to run on modesetting.

I hope it helps