Description of problem:

The mode timings of the default 640x480-60 mode in
drivers/video/vga16fb.c do not work with some LCD displays 
because they deviate slightly from the standard. In particular, the
screen height is wrong (529 vs. 525 pixels)

Version-Release number of selected component (if applicable):
2.4.21-20.EL and all others

How reproducible:
E.g. Installing RH on a system with an LCD screen that can't hanlde
slightly wrong VGA timings, without the "nofb" installation option.

Steps to Reproduce:
1.Install RH 

Actual results:
Screen will become black (or garbled, depending on display device)
after loader starts


Expected results:
Screen remains readable

Additional info:
I'll attach a patch. Problem was already discussed on the
linux-fbdev-devel mailing list.