Comment # 3 on bug 1004453 from Egbert Eich

vga= is not supported by grub2 any more. AFAIR, Felix is using a grub1 setup
and starts the Xserver using 'startx' (probably as a regular user) with some
scripts on top.
startx really isn't supported any more either - which doesn't mean it won't
work, however one needs to know very well what needs to be done to make it
work.

Felix: Does it work when you do the same as 'root'?

This may be due newer kernels not allowing to share iomem between drivers -
see:
bsc#971907 
Or it may be due to PCI ROM not being made accessible. See the pci=.. command
line option.