Comment 11 for bug 1230008

I can't say anything about "flashes screen".
But:

ubuntu 14.04, 64 bit,
nvidia (331.38) and bumblebee (3.2.1-90)

before using optirun,
"optirun --status":
Bumblebee status: Ready (3.2.1). X inactive. Discrete video card is off.

After using optirun,
"optirun --status":
Bumblebee status: Error (3.2.1): [XORG] (EE) Server terminated successfully (0). Closing log file.

Problem can be solved by 'sudo service bumblebeed restart'.