This also requires root privs, like DGA (curses!). Unlike DGA, you
can't fix it with SGID perms on mplayer and /dev/mem (which implies
that GtK GUI mode won't work, as this stops running if the EUID is 0)
Xvidix seems to needs to open the video device as root, and there
are only a limited number of built-in graphics devices (happily
from my POV, Mach64 is one of them).
To OP (I forget who that was), all these methods work fullscreen for
me. The best description of my card is:
[earth] /home/paul: scanpci
pci bus 0x0001 cardnum 0x00 function 0x00: vendor 0x1002 device 0x5046
ATI Technologies Inc Rage 128 PF/PRO AGP 4x TMDS
If it is not just a mis-configuration on your part then I guess there
is a (major) difference between the Rage PRO and the Rage 128 PRO.
(Where I bought the computer from, they called it "Rage Fury PRO")