I recently installed a Tesla k20c on a Ubuntu 12.04 64bit machine. Unfortunately, even the earliest drivers (310.09) are not packaged in the official repositories. So, I installed the latest one (313.19 beta) from https://launchpad.net/~xorg-edgers/+archive/ppa. The installation went fine and the driver recognized k20c fine. I was even able to run a few opencl test programs. However, once a gpu program fails (for any reason), I cannot run any gpu code unless I restart the machine. The reason is when I call clCreateContext for the Tesla, it hangs forever. Did anybody have a similar issue? Also, if anybody got the k20c working under ubuntu 12.04 64bit, which driver are you using?