Comment 7 for bug 1401784

Just for anyone who wants to turn DR3 back, here is the solution I found:

- You need to have a DRI3 enabled xserver-xorg-video-intel driver. You can get one from the xorg-edgers ppa. I just downloaded the deb file that suits for my Ubuntu architecture from here: https://launchpad.net/~xorg-edgers/+archive/ubuntu/ppa/+packages?field.name_filter=&field.status_filter=published&field.series_filter=vivid

After that just do
sudo dpkg -i ./name_of_the_debfile

- xorg configuration needs adjustments. Just do
sudo vi /etc/X11/xorg.conf

and insert:

Section "Module"
        Load "dri3"
EndSection

Section "Device"
  Identifier "Intel"
  Option "DRI" "3"
EndSection

Now everything runs much smoother, without a sign of tearing.