Comment 9 for bug 1507676

I have similar issue Ubuntu 14.04 LTS (14.04.4 kernel 4.2.0-30-generic) Nvidia geforce 940M
Tried different driver version (331,346,352,355,361) from different sources.

PPA: xorg-edgers - black screen
PPA: graphics-drivers - infinite login loop
http://www.nvidia.pl/download/driverResults.aspx/98425/pl - black screen
and 352 driver from Ubuntu 14.04.4 CD... - this pretends to work on kernel 4.2.0-27-generic, but when you want to switch to performance mode you will get:

Error: alternatives are not set up properly
Error: nvidia mode can't be enabled

And moreover any tool/application using 3D gl graphics is not using nvidia gpu :-(

https://devtalk.nvidia.com/default/topic/921922/linux/nvidia-getforce-gtx-950m-gddr3-black-screen-or-login-loop-when-install-nvidia-driver/?offset=2#4828839