Ubuntu – NVidia graphic card disappeared after bug with nvidia-prime (Ubuntu 14.04)

14.04driversnvidianvidia-prime

I have a really strange problem on my Ubuntu (and on my whole computer now).
Some days ago, my computer began to take a very long time to boot (2-3 minutes). Thus, I reached out for help in order to see where the problem came from. I solved it by reinstalling my nVidia drivers, and going from bumblebee to prime. It worked, my computer booted faster, very well. First thing I did was however to select the Intel card as my principal graphics card.

Today, I wanted to play some games, so I tried to revert it to the nvidia card. I got the same problem as was already described here : Can't switch anymore from Intel to NVIDIA GPU . I tried one of the solutions, it seemed to work (I was able to switch), but when I logged out, my computer just hang. I reconnected using tty2, and forced a reboot. After that, I was unable to log into X again. After a few tries, I decided to remove the prime drivers and get back to bumblebee.

Now for the strange part : my graphics card seems to have completely disappeared from my system. It is not recognized by my Windows 8.1 anymore (before my troubles on Ubuntu, I had no problem with my graphics card on Windows). Furthermore, when I installed bumblebee, it complained that I had no nVidia graphics card on my system. There is also only one listed VGA device on lscpi : my integrated Intel chip. https://askubuntu.com/users/272018/user5288 seems to have had the same problem, but it was never resolved it seems. Does anybody know how to resolve this ?

Btw, I'm running Ubuntu 14.04 on a Dell Inspiron 7720 with a nVidia GT 750M (before it disappeared…)

Thanks in advance.

Edit : problem finally solved. Reinstalling the drivers did not work at first. However, I've got an other advice on a different forum : unplug the power supply, remove the battery, wait for about ten seconds (I also pressed on the power button for ten seconds, doesn't know if it helped). After this, I booted, the graphics card was recognized under Windows. I reinstalled the nvidia drivers and now everything works fine ! Thanks 🙂

Best Answer

Step 1 : Remove all NVIDIA related software you installed.

Highlight the Ubuntu menu entry and press the E key.
Add nouveau.modeset=0 to the end of the linux line.
Press the F10 key to boot into the Ubuntu system.

When the login screen appears press Ctrl+Alt+F1.
Enter your user name and password ... then execute : 

sudo apt-get purge nvidia* bumblebee
sudo reboot

Step 2 : Reinstall the NVIDIA drivers and Optimus support.

Highlight the Ubuntu menu entry and press the E key.
Add nouveau.modeset=0 to the end of the linux line.
Press the F10 key to boot into the Ubuntu system.

When the login screen appears press Ctrl+Alt+F1.
Enter your user name and password ... then execute : 

sudo apt-get update
sudo apt-get install nvidia-352 nvidia-prime
sudo reboot
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