Comment 19 for bug 1316035

Just confirming, same thing here on an IBM x3500 M3:

  *-display UNCLAIMED
       description: VGA compatible controller
       product: MGA G200EV
       vendor: Matrox Electronics Systems Ltd.
       physical id: 0
       bus info: pci@0000:07:00.0
       version: 00
       width: 32 bits
       clock: 33MHz
       capabilities: pm vga_controller bus_master cap_list
       configuration: latency=64 maxlatency=32 mingnt=16
       resources: memory:96000000-96ffffff memory:97800000-97803fff memory:97000000-977fffff

Also:

$ lsmod | grep mg
$ sudo modprobe mga
$ lsmod | grep mg
mga 40811 0
drm 303102 1 mga

Tried a recommended xorg.conf:
Section "Device"
        Identifier "Matrox Graphics, Inc. MGA G200 AGP2"
        Driver "mga"
        Option "OldDmaInit" "True"
EndSection

Doesn't help, as expected after Zoltán's comments.