there's a linux driver for the S3 Unichrome video chipset (used in VIA KM400-based motherboards) hanging around the net (namely at www.viaarena.com), but there's no support for it in Fedora Core test1 setup. I can only manage to run X in VESA-compatible mode. the VIA installer crashes as it doesn't recognize Fedora. moreover I'm not sure if that driver is compatible with the new 2.6 series kernel.
I've got the same problem: dmesg says "chipset unsupported" (I've got a motherboard with VIA KM400)... I'm using a Radeon 7000 instead of the internal device. X works, but SLOW (no agp module, no direct rendering...)
Still unsupported in FC2-test2. Could not complete installation (X dies on first reboot with "Screens found, but no usable configuration" or something like that, using the vesa driver chosen by the installer). I copied over a known working XFConfig file and got X to start successfully using the "via" X driver, but got "Failed to load kernel module agpgart" and "failed to load kernel module "via" in /var/log/XFree86.0.log. I'm using an Asus A7V8X-MX motherboard with the KM400 chipset.
www.viaarena.com released module sources for kernel 2.4. You need the kernel sources AND the Via files, they give you step-by-step instrucions to compile and install the module. I didn't work for me, but I know nothing about kernel compiling (so I hate to say it, but I have to say it, it's probably me...)
Since this bugzilla report was filed, there have been several updates to the via driver included in Fedora Core. Users are encouraged to upgrade to the latest version of Fedora Core, which can be obtained from: http://fedora.redhat.com/download If the included driver is lacking functionality you would like to see in a future X.Org release, please file a bug report in the X.Org bugzilla at http://bugs.freedesktop.org in the "xorg" component, pointing to any external driver sources which are newer, and indicating it is a feature enhancement request. Once you've filed your bug report to X.Org, it will be tracked by X.Org developers, and once reviewed for consideration, a future X.Org release may provide the requested functionality.