I use Gentoo Linux (kernel 3.15.1, problem exists also with earlier kernels) on Lenovo Ideapad Z570 with Optimus (NVidia GeForce 630M). Driver version is 331.79 (problem exists also with 340.17). I use primusrun to run games (e.g. Portal 2 with Steam) on NVidia card. When I launch the game and play some minutes, the game hangs (it is even impossible to kill is with kill -9, zombie remains with child thread consuming 100% cpu) and the following message in kernel log appears:
NVRM: GPU at 0000:01:00.0 has fallen off the bus.
After that it is possible to restore computer functionality only after cold reboot. If I do hot reboot, computer hangs with black screen when it starts booting UEFI.
The first thought was about broken hardware, but I did some diagnostics and found out that with driver 304.121 all things work, there is no hangs, I was able to play game much longer than it takes to hang with driver 331.79. Also I tried playing under Windows 8.1, the game was also hanging but after some seconds the game continued.
Here is nvidia-bug-report.sh output: http://pastebin.com/Q4xbvxg5
Here is Xorg.8.log (bumblebee X-server): http://pastebin.com/qa9JeSKV
Please help me with this problem, it is really bad idea to stick with old drivers.