I tried it many times and finally installed CUDA 7.5 on my laptop (Nvidia GeForce 750M) with optimus. It was very tricky but these steps worked for me.
Step 1: Switch to kubuntu.
(Some other linux desktop should also work, e.g. lubuntu, mate) According to this tutorial, both Ubuntu Unity and Gnome3 desktops were very susceptible to black-screen states and/or corrupted workspaces. KDE didn’t seem to suffer from these problems. Following commands can help you to do the switch:
sudo apt-get install kubuntu-desktop build-essential emacs synaptic dkms
sudo apt-get upgrade
sudo shutdown -r now
In my case after making sure Kubuntu working properly I removed the default ubuntu desktop by using
sudo apt-get remove ubuntu-desktop
Step 2: Install the nvidia driver for your graphics card.
NVidia 352.79 is the one I used. This step is actually optional. Skipping this step without any nvidia driver installed should also work.
Step 3: Download and install cuda toolkit deb local installer file.
Because the .run installer did not work for me, I strongly recommend using the deb file.
sudo dpkg -i cuda-repo-ubuntu1404-7-5-local_7.5-18_amd64.deb
sudo apt-get update
sudo apt-get install cuda
Step 4: Possible troubleshooting.
During the installation(sudo apt-get install cuda), an error of unmet dependencies happened to me. I tracked down the problem and uninstalled the conflicting package by following this tutorial by @osdf here.
Step 5: Load module for CUDA.
Run this command and you are hopefully free to use CUDA on your machine.
modprobe nvidia_uvm