Comment 4 for bug 236006

Similar symptoms appear with MGA G200 AGP on a uptodate hardy system. With upgrade to hardy the highest possible resolution reduced to 800x600@60 Hz (the hardware supports at least 1280x1024@75 Hz).

matthias@hans:~$ cat /etc/X11/xorg.conf
# xorg.conf (X.Org X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "InputDevice"
 Identifier "Generic Keyboard"
 Driver "kbd"
 Option "XkbRules" "xorg"
 Option "XkbModel" "pc105"
 Option "XkbLayout" "de"
 Option "XkbVariant" "nodeadkeys"
 Option "XkbOptions" "lv3:ralt_switch"
EndSection

Section "InputDevice"
 Identifier "Configured Mouse"
 Driver "mouse"
 Option "CorePointer"
EndSection

Section "Device"
 Identifier "Configured Video Device"
EndSection

Section "Monitor"
 Identifier "Configured Monitor"
EndSection

Section "Screen"
 Identifier "Default Screen"
 Monitor "Configured Monitor"
 Device "Configured Video Device"
EndSection

Section "ServerLayout"
 Identifier "Default Layout"
 Screen "Default Screen"
EndSection

matthias@hans:~$ lspci -nn | grep VGA
01:00.0 VGA compatible controller [0300]: Matrox Graphics, Inc. MGA G200 AGP [102b:0521] (rev 03)

matthias@hans:~$ sudo ddcprobe
[sudo] password for matthias:
Calling INT 0x42 (F000:F065)
 EAX is 0xBD50
vbe: VESA 2.0 detected.
oem: Matrox Graphics Inc.
memory: 2048kb
mode: 640x400x256
mode: 640x480x256
mode: 800x600x16
mode: 800x600x256
mode: 1024x768x256
mode: 1280x1024x256
mode: 80x60 (text)
mode: 132x25 (text)
mode: 132x43 (text)
mode: 132x50 (text)
mode: 132x60 (text)
mode: 640x480x32k
mode: 640x480x64k
mode: 640x480x16m
mode: 800x600x32k
mode: 800x600x64k
mode: 800x600x16m
mode: 1024x768x32k
mode: 1024x768x64k
edid:
edidfail

matthias@hans:~$ xrandr
Screen 0: minimum 400 x 300, current 800 x 600, maximum 800 x 600
default connected 800x600+0+0 0mm x 0mm
   800x600 60.0* 56.0
   640x480 60.0
   400x300 60.0 56.0
matthias@hans:~$