After patching 2.2.16-3 as I explained in bug 13424, X is broken in more subtle way, meaning that you can start X, but switching from X to the console and back garbles screen with an i810-DC100 chipset. This didn't happened with the good old 2.2.14-12. Not much QC at RedHat these days...
Umm we dont support user hacked up kernels, and the i810 stuff of this period had plenty of bugs. I think this one is(was rather) an X server bug looking at the stuff on my i810 and the X ChangeLog for 4.0