Nvidia Optimus tear free test

The purpose here is to test whether adding a tearfree line to xorg.conf is effective in reducing tearing on nvidia optimus gpu's when using the nvidia drivers.
This is done thru adding a TearFree option to xorg.conf for the Intel device when xorg.conf is generated or regenerated by gpu-manager

** Here it has no effect on a standard 14.04.1 install with non lts HWE mesa stack. Tear Free is enabled, then immediately disabled, seen clearly in /var/log/Xorg.0.log. Works fine with 14.04.1 upgraded to the vivid HWE lts stack, 14.04.3, 15.04 & 15.10 **

** Also note that this does introduce some minor tearing while moving cursor inside a video window, for me small price to be paid **

Tested here with a nvidia GeForce GT 755M in an ubuntu session & this ppa's nvidia drivers, both 340, 355 & 358. 355/358 seemed best
*Trusty users should probably use drivers from below ppa*, for vivid, wily doesn't hurt either, 355 or higher beats the 352 drivers

https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa

To try, *assumes already using nvidia-prime* -

Upgrade to the ppa's ubuntu-drivers-common package

If currently on Nvidia -
open nvidia settings, switch to Intel, log out/in
open nvidia settings, switch to nvidia, log out/in
See how it goes

If currently on Intel -
open nvidia settings, switch to nvidia, log out/in
See how it goes

To ck. - open /etc/X11/xorg.conf, you should see this line in intel device section, Option "TearFree" "True"
example here of complete section

Section "Device"
    Identifier "intel"
    Driver "intel"
    BusID "PCI:0@0:2:0"
    Option "AccelMethod" "SNA"
    Option "TearFree" "True"
EndSection

To add this ppa -
sudo add-apt-repository ppa:mc3man/tearfree-test
sudo apt-get update

To remove this ppa & revert back -
Install ppa-purge
sudo ppa-purge ppa:mc3man/tearfree-test

Note: PRIME Synchronization will be working in 16.04.3, instructions here
https://ubuntuforums.org/showthread.php?t=2365449