I have the same problem.
What I did :
- added kernel parameter "pci=bios" (found that it may help)
- command lspci - v -v -> the SiS900 is recodnized
- modprobe sis900 -> error
- dmesg -> "v1.08.04 4/25/2002 ... eth0 : Error EERPOM read fff"
I've then checked on a forum and found this thread :
The version of SiS900 in RedHat 8.0 seems to be too old ! I hae no idea, how we can update this module...