8. Frequently Asked Questions

How do I install the Toolkit in a different location?

The Runfile installation asks where you wish to install the Toolkit and the Samples during an interactive install. If installing using a non-interactive install, you can use the --toolkitpath and --samplespath parameters to change the install location:

$ ./runfile.run --silent \
                --toolkit --toolkitpath=/my/new/toolkit \
                --samples --samplespath=/my/new/samples

The RPM and Deb packages cannot be installed to a custom install location directly using the package managers. See the "Install CUDA to a specific directory using the Package Manager installation method" scenario in the Advanced Setup section for more information.

Why do I see "nvcc: No such file or directory" when I try to build a CUDA application?

Your PATH environment variable is not set up correctly. Ensure that your PATH includes the bin directory where you installed the Toolkit, usually /usr/local/cuda-8.0/bin.

$ export PATH=/usr/local/cuda-8.0/bin${PATH:+:${PATH}}

Why do I see "error while loading shared libraries: : cannot open shared object file: No such file or directory" when I try to run a CUDA application that uses a CUDA library?

Your LD_LIBRARY_PATH environment variable is not set up correctly. Ensure that your LD_LIBRARY_PATH includes the lib and/or lib64 directory where you installed the Toolkit, usually /usr/local/cuda-8.0/lib{,64}:

$ export LD_LIBRARY_PATH=/usr/local/cuda-8.0/lib\
                         ${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}

Why do I see multiple "404 Not Found" errors when updating my repository meta-data on Ubuntu?

These errors occur after adding a foreign architecture because apt is attempting to query for each architecture within each repository listed in the system's sources.list file. Repositories that do not host packages for the newly added architecture will present this error. While noisy, the error itself does no harm. Please see the Advanced Setup section for details on how to modify your sources.list file to prevent these errors.

How can I tell X to ignore a GPU for compute-only use?

To make sure X doesn't use a certain GPU for display, you need to specify which other GPU to use for display. For more information, please refer to the "Use a specific GPU for rendering the display" scenario in the Advanced Setup section.

Why doesn't the cuda-repo package install the CUDA Toolkit and Drivers?

When using RPM or Deb, the downloaded package is a repository package. Such a package only informs the package manager where to find the actual installation packages, but will not install them.
See the Package Manager Installation section for more details.

How do I get CUDA to work on a laptop with an iGPU and a dGPU running Ubuntu14.04?

After installing CUDA, set the driver value for the intel device in /etc/X11/xorg.conf to 'modesetting' as shown below:

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    ...
EndSection

To prevent Ubuntu from reverting the change in xorg.conf, edit /etc/default/grub to add "nogpumanager" to GRUB_CMDLINE_LINUX_DEFAULT. Run the following command to update grub before rebooting:

$ sudo update-grub

What do I do if the display does not load after updating the Linux kernel on Fedora?

The Akmods framework will sometimes fail to correctly rebuild the NVIDIA kernel module packages when a new Linux kernel is installed. When this happens, it is usually sufficient to invoke Akmods manually and regenerate the module mapping files by running the following commands in a virtual console, and then rebooting:

$ sudo akmods --force
$ sudo depmod

You can reach a virtual console by hitting ctrl+alt+f2 at the same time.