[nvidia-331-updates] [14.10 Utopic] CUDA only works as root

[YAFU]

Using Kubuntu 14.10 64bits
==========
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Utopic Unicorn (development branch)
Release: 14.10
Codename: utopic
==========
$ sudo dpkg -l | grep -i nvidia
ii bbswitch-dkms 0.7-2ubuntu1 amd64 Interface for toggling the power on nVidia Optimus video cards
ii libcuda1-331-updates 331.89-0ubuntu5 amd64 NVIDIA CUDA runtime library
ii nvidia-331-updates 331.89-0ubuntu5 amd64 NVIDIA binary driver - version 331.89
ii nvidia-331-updates-uvm 331.89-0ubuntu5 amd64 NVIDIA Unified Memory kernel module
ii nvidia-opencl-icd-331-updates 331.89-0ubuntu5 amd64 NVIDIA OpenCL ICD
ii nvidia-prime 0.6.6 amd64 Tools to enable NVIDIA's Prime
ii nvidia-settings 331.20-0ubuntu8 amd64 Tool for configuring the NVIDIA graphics driver
==========
$ lsmod | grep nvi
nvidia 10728519 40
drm 310919 3 nvidia
========================================

I am using the Blender 3D 2.71 binary downloaded from the official Blender site. It contain precompiled CUDA Kernel (cuda toolkit is not required to be installed). If I run Blender then CUDA is not available under "File > User Preferences > System > Compute Device" . If I run as super user Blender (kdesudo ./blender), then CUDA is available.
Here's a related thread on nvidia devtalk forum (see message #8):

https://devtalk.nvidia.com/default/topic/699610/334-21-driver-returns-999-on-cuinit-cuda-/

[YAFU (yafu)]

I think maybe this report is related with this:
https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-331/+bug/1361207

[YAFU (yafu)]

Well, I installed the "nvidia-modprobe" package and that seems to solve the problem.
$ lsmod | grep nvi
nvidia_uvm 34855 0
nvidia 10728519 41 nvidia_uvm
drm 310919 3 nvidia

Definitely when the nvidia drive is installed then "nvidia-modprobe" should be automatically installed as a dependency.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Thomas Beck (coktzct)]

I had exactly the same problem with an nvidia-prime notebook (Lenovo Flex 2) and solved it exactly as you (Yafu) did - thanks for digging!

I really hope that this will be a dependancy before 14-10 is released.