Ubuntu 14.04. Error: cudaGetDeviceCount returned 30

I try to use cuda_8.0.61_375.26_linux.run on ubuntu14.04.
when I want to try NVIDIA_CUDA-8.0_Samples/bin/x86_64/linux/release, got error.
When I run ./deviceQuery I get this result.
How can I fix it?

----------------this is message in terminal----------------------
./deviceQuery Starting…

CUDA Device Query (Runtime API) version (CUDART static linking)

cudaGetDeviceCount returned 30
→ unknown error
Result = FAIL

thanks for help

@d19931217b, I had the same problem 30 mins ago and I have managed to get it to work by running deviceQuery as sudo. After the first time running as sudo, it works fine thereafter without sudo.

$ sudo ./deviceQuery

I don’t yet understand how/why this works. Will post back if I find the answer.

@reginaldg, I try

sudo ./deviceQuery

but i got the same error message.
Hope you can tell me the answer.