matrox G550 on FreeBSD 4.9-release

[Burke Chih-Jen Ko]

I am running on FreeBSD 4.9-release and with hardward set up as below:

Mainboard: ABIT NF7-s, nVidia nForce 2 ultra 400 chipset
Graphic adapter: Matrox Millenium G550

Having searched the archive, I found most discussions are related and 
XFree86, and googled with error message below, I tried several 
solutions but no one worked. What should I do to avoid the dmesg error?
Here is the message:

drm0: <Matrox G550 (AGP)> mem 
0xe7000000-0xe77fffff,0xe6000000-0xe6003fff,0xe4000000-0xe5ffffff irq 
10 at device 0.0 on pci2
error: [drm:mga_init] *ERROR* Cannot initialize the agpgart module.
device_probe_and_attach: drm0 attach returned 12

and my kernel is compiled with
device vga
device agp
device mgadrm

base on information provide with this link, I don't load agp in 
loader.conf:
http://lists.freebsd.org/pipermail/freebsd-stable/2003-May/001031.html

then following are some of links I've visited:
http://lists.freebsd.org/pipermail/freebsd-stable/2003-May/001032.html
http://lists.freebsd.org/pipermail/freebsd-stable/2003-May/001030.html
http://groups.yahoo.com/group/freebsd-multimedia/message/12842?source=1
http://people.freebsd.org/~anholt/dri/index.html
http://www.luna2.org/~yatt/freebsd/dri.shtml

any hints or solutions will be appreciated!

sincerely,
Burke