Please note: above trouble with today's rc kernel 3.18-rc2 is a *regression*
from  the stock kernel that comes w/ linux mint-qiana-17:  Linux version
3.13.0-39-generic (buildd@toyol) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) )
#66-Ubuntu SMP Tue Oct 28 13:30:27 UTC 2014

The stock kernel seems to mostly work fine-ish, for both 3D (i.e. blender) and
youtube.  Halting and restarting X does ggenerate the 'failed to idle' messages
.. but since I never restart X, I can live w/it.

BTW: noveau 2d rendering rocks, much faster than the nvidia drivers, which are
noticeably laggy and slow for exactly the same hw & os setup.