The dkms version of the Nvidia driver is a great convenience, yet it usually means you wont have the latest version and when the kernel updates, that can be a problem. Like Today.
Running CentOS 6 on our workstations and decided time to update packages and I hoped dkms wouldn’t let me down, but it did. So boot into run level 3 and remove dkms and the dkms nvidia driver to make way for the latest version. Its normally a straight forward process, yet Nvidia can mess up the xorg installation, like it did for me. Some how libwfb.so was missing, so the Nvidia driver will install its own version.
This doesn’t work as you’ll get a message about unknown symbol PictureScreenPrivateIndex. Turns out for some installations that don’t have libwfb, Nvidia brings its own, yet since I’m supposed to have it, this led to trouble. The quick fix is to reinstall the right package. Use yum whatprovides */libwfb.so to find that xorg-x11-server-Xorg is the correct package and yum reinstall restores libwfb. Install the Nvidia driver via the script as usual and you should be good to go.