Comment 1 for bug 276946

Could this be caused my installing the nvidia restricted drivers (177) via jockey-kde?

I'm current version of jockey-kde is 0.5~beta1-0ubuntu1. But I'm not sure which particular version of jockey-kde I used for installing nvidia drivers.

dpkg -l | grep nvidia:
ii nvidia-173-modaliases 173.14.12-1-0ubuntu3 Modaliases for the NVIDIA binary X.Org drive
ii nvidia-177-kernel-source 177.76-0ubuntu1 NVIDIA binary kernel module source
ii nvidia-177-modaliases 177.76-0ubuntu1 Modaliases for the NVIDIA binary X.Org drive
ii nvidia-71-modaliases 71.86.04-0ubuntu10 Modaliases for the NVIDIA binary X.Org drive
ii nvidia-96-modaliases 96.43.05-0ubuntu10 Modaliases for the NVIDIA binary X.Org drive
ii nvidia-common 0.2.3 Find obsolete NVIDIA drivers
rc nvidia-glx-173 173.14.12-1-0ubuntu3 NVIDIA binary Xorg driver
ii nvidia-glx-177 177.76-0ubuntu1 NVIDIA binary Xorg driver
ii nvidia-settings 173.14.09-1ubuntu3 Tool of configuring the NVIDIA graphics driv