Framebuffer console with a G400

[Mark Zimmerman <mark@zman.terra.co.us>]

Greetings:

I'm trying to get a better than VGA resolution on the console with a
G400 card. So far, I've gotten the console driver to work minimally
but I can't get it into a mode I want.

Here's what I get in dmesg:

matroxfb: Matrox unknown G400 (AGP) detected
Invalid vesa mode 0x01B8
matroxfb: 640x480x0bpp (virtual: 640x13104)
matroxfb: framebuffer at 0xCE000000, mapped to 0xd0005000, size
16777216
Console: switching to colour frame buffer device 80x30
fb0: MATROX VGA frame buffer device

fbset -i tells me this:

mode "640x480-60"
    # D: 25.200 MHz, H: 31.500 kHz, V: 59.999 Hz
    geometry 640 480 640 13104 0
    timings 39683 48 16 33 10 96 2
    accel true
    rgba 6/0,6/0,6/0,0/0
endmode

Frame buffer device information:
    Name        : MATROX
    Address     : 0xce000000
    Size        : 16773120
    Type        : MGA Millennium I step 16 text
    Visual      : PSEUDOCOLOR
    XPanStep    : 8
    YPanStep    : 1
    YWrapStep   : 0
    LineLength  : 1280
    MMIO Address: 0xcd000000
    MMIO Size   : 16384
    Accelerator : Matrox G400

But when I use fbset to change modes, (even if I specify the current
mode) I get this:

owl:~# fbset 640x480-60
ioctl FBIOPUT_VSCREENINFO: Invalid argument

Has anyone out there had better success with a G400?

-- Mark