Comment 18 for bug 1362848

I fixed the problem with my nvidia graphic card using the post #15.

Thank you very much kcpr (mkasprzyk5) without your help I would not be albe to fix it.

Here how I fixed in details:

Log out and go to the console:

CTRL-ALT-F1

if (like me) you tried to install latest nvidia driver (nvidia-340 ...), you need to revert back with following commands:

sudo apt-get install ppa-purge
sudo ppa-purge xorg-edgers
sudo apt-get purge nvidia*

Then copy all xorg config files in a temporary dir:

cd
mkdir temp
sudo mv /etc/X11/xorg.conf* ./temp/

Then clean, update, upgrade and reboot the system:

sudo apt-get autoremove
sudo apt-get update
sudo apt-get upgrade
sudo reboot

Go to the console:

CTRL-ALT-F1

Install nvidia 331:

sudo apt-get install nvidia-331 nvidia-prime

Copy the old xorg.conf made by nvidia back in its directory:

sudo cp temp/xorg.conf.nvidia-xconfig-original /etc/X11/xorg.conf

And edit it (I used vi, you may prefer nano):

sudo vi /etc/X11/xorg.conf

To be as the following:

Section "ServerLayout"
    Identifier "layout"
    Screen 0 "nvidia"
    Inactive "intel"
EndSection

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

Section "Screen"
    Identifier "intel"
    Device "intel"
EndSection

Section "Device"
    Identifier "nvidia"
    Driver "nvidia"
    BusID "PCI:1@0:0:0"
    Option "ConstrainCursor" "off"
EndSection

Section "Screen"
    Identifier "nvidia"
    Device "nvidia"
    Option "AllowEmptyInitialConfiguration" "on"
    Option "IgnoreDisplayDevices" "CRT"
EndSection

Eventually reboot the system:

sudo reboot

Now I have nvidia set as graphic card and the hardware acceleration works fine.