Comment # 17 on bug 1201398 from Stefan Dirsch

(In reply to Yakun Li from comment #16)
> (In reply to Stefan Dirsch from comment #14)
> > Hmm. Shot in the dark. Try with
> > 
> > Section "Device"
> >     Identifier "modesetting"
> >     Driver "modesetting"
> >    Option "AccelMethod" "none"
> > EndSection
> > 
> > instead of
> > 
> > Section "Device"
> >     Identifier "modesetting"
> >     Driver "modesetting"
> > EndSection
> > 
> > (i.e. add this Option line) in /etc/X11/xorg.conf.d/90-nvidia.conf file.
> 
> Hi, I tried with what you suggested, unfortunately it did not work, the
> corresponding log is attached. This 90-nvidia.conf file did not exist

Weird. That means that the command 'prime-select nvidia' never finished. :-(

> on the  system and I created it with the content you shared.

Well, that cannot work. Better remove it again.