Actually, you can pass options to the kernel, but not through "vga=... " You need vga=normal only to disable the eventually coinstalled vesa...
Moreover, I manage to make it work fine on my 15' screen of a Compaq Presario 2120, with the maximum resolution of 1024x768 automatically detected from the bios. The troubles which I explain above disappear, passing the "noaccel" option to the kernel... The acceleration in the framebuffer is not very useful and I can live fine without it!!!!
The only remaining troubles are:
1) a bit of strange colours when the boot-penguin appears;
2) in the first 4-5 seconds of the boot-up, the resolution is that of the previous vesafb... It seems that radeonfb is used afterwards. Very unimportant troubles, in my opinion... I read somewhere googling that they are well-known bugs.
I passed these options to the kernel (adding it to the kernel line in grub.conf):
video=radeonfb:1024x768,noaccel
I think that, in this way, also the resolution you like is substituted to that taken from the bios, but I'm not sure, since in my situation they coincide... Note that after "video=" you have to write "radeonfb" only in 2.5 and above kernels... in 2.4 kernels write "radeon" instead, without "fb"...
You find a complete how-to for radeonfb, with many more options and their detailed syntax at this address:
http://thesapphirecat.iwarp.com/present ... eonfb.html
The author affirms that his guide has to be referred to 2.4 kernels only... But I can tell you that the only differences in the newer kernels concern the change of name from "radeon" to "radeonfb"

))
Giorgio Lando