Comment 2 for bug 1438106

Confirm

Exact same problem for me.

15.04 beta 2, nvidia-346

timo@Timo-NB:~$ glxgears
Xlib: extension "GLX" missing on display ":0.0".
Error: couldn't get an RGB, Double-buffered visual

timo@Timo-NB:~$ sudo optirun nvidia-settings
[ 1484.024073] [ERROR]Cannot access secondary GPU - error: Could not load GPU driver

[ 1484.024179] [ERROR]Aborting because fallback start is disabled.

timo@Timo-NB:~$ sudo service bumblebeed status
● bumblebeed.service - Bumblebee C Daemon
   Loaded: loaded (/lib/systemd/system/bumblebeed.service; enabled; vendor preset: enabled)
   Active: active (running) since Di 2015-03-31 20:14:01 CEST; 26min ago
 Main PID: 735 (bumblebeed)
   CGroup: /system.slice/bumblebeed.service
           └─735 /usr/sbin/bumblebeed

Mär 31 20:14:41 Timo-NB bumblebeed[735]: [ 43.334347] [ERROR]Module nouveau could not be loaded (timeout?)
Mär 31 20:14:41 Timo-NB bumblebeed[735]: [ 43.334360] [ERROR]Could not load GPU driver
Mär 31 20:19:49 Timo-NB bumblebeed[735]: modprobe: ERROR: ../libkmod/libkmod-module.c:816 kmod_module_insert_module() could not find module by name='off'
Mär 31 20:19:49 Timo-NB bumblebeed[735]: modprobe: ERROR: could not insert 'off': Function not implemented
Mär 31 20:19:49 Timo-NB bumblebeed[735]: [ 352.023899] [ERROR]Module nouveau could not be loaded (timeout?)
Mär 31 20:19:49 Timo-NB bumblebeed[735]: [ 352.023919] [ERROR]Could not load GPU driver
Mär 31 20:38:41 Timo-NB bumblebeed[735]: modprobe: ERROR: ../libkmod/libkmod-module.c:816 kmod_module_insert_module() could not find module by name='off'
Mär 31 20:38:41 Timo-NB bumblebeed[735]: modprobe: ERROR: could not insert 'off': Function not implemented
Mär 31 20:38:41 Timo-NB bumblebeed[735]: [ 1484.023970] [ERROR]Module nouveau could not be loaded (timeout?)
Mär 31 20:38:41 Timo-NB bumblebeed[735]: [ 1484.023992] [ERROR]Could not load GPU driver