While using the 3.16 kernel, I can't seemed to boot into the graphical login. Is all blank page. It was perfectly fine using the 3.11 kernel.
$ uname -sr Linux 3.16.2-201.fc20.x86_64
In the end, I've to switch to the console login by Ctrl-Alt-F2, and checking the systemd journal log. Sample error message relating the Nouveau driver as shown.
$ journalctl -r | grep nouveau Sep 27 11:23:24 butterfly kernel: nouveau E[ PFIFO][0000:01:00.0] CACHE_ERROR - ch 0 [DRM] subc 2 mthd 0x0130 data 0x0000000 ...... Sep 27 10:16:43 butterfly kernel: nouveau E[ DRM] GPU lockup - switching to software fbcon
Some quick search revealed that to stop the X from freezing during startup, you've to disable Nouveau acceleration, which is the common, typical, and conventional solution. There are two ways.
First, adding 'nouveau.nofbaccel=1' to the kernel parameter. This can be done during Grub2 bootup by pressing 'e' and append, after the 'rhgb quiet' the option line to the kernel parameter. It looks something like below.
...rhgh quiet nouveau.nofbaccel=1
Later, just press F10 key to continue booting the system. However, you'll have to do this everything you boot up your machine.
Second, to make this a permanent solution, you'll need to modify the Grub2 configuration. Again, there are two ways to do so.
Edit the /etc/default/grub and append 'nouveau.nofbaccel=1' to the line GRUB_CMDLINE_LINUX and update the Grub2.
$ sudo grub2-mkconfig --output=/boot/grub2/grub.cfg
Another approach is the set the configuration through module configuration file when the kernel is loading. I prefer this option as it is easier to change than using the Grub2 way.
$ sudo sh -c 'echo "options nouveau nofbaccel=1' > /etc/modprobe.d/nouveau.conf "
You may ask, why not using the proprietary Nvidia driver? Well, unfortunately, I can't get it to work correctly, especially with latest 3.16 kernel. And, I don't want to waste my time on troubleshooting the same issue again and again.
Stuck with Nouveau driver forced me to switch my desktop environment from Gnome 3 to Xfce4. I've learned that without well-supported graphic card driver, Gnome 3 experience still a lot to be desired. Mind you, this workstation is running on 20GB ram and yet, it does not help.
While not as fancy as Gnome 3, Xfce4 seems acceptable for my daily usage compare to other desktop environment.