Getting Xorg to Work for Ubuntu 10.04 on the iMac G3

If you feel so inclined to install Ubuntu 10.04 on an iMac G3 you’ll find that xorg doesn’t work properly without some adjustment. I found the answer as per this forum post.

Create /etc/X11/xorg.conf then paste the contents from below into it.

# 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" "pc104"
Option "XkbLayout" "us"
EndSection
Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
EndSection
Section "Device"
Identifier "ATI Technologies Inc Rage 128 RL/VR AGP"
Driver "r128"
# Option "BusID" "PCI:0000:00:10.0"
# Option "Screen" "0"
# Option "VideoRam" "128000"
# Option "MemBase" ""
# Option "IOBase" ""
# Option "ChipID" ""
# Option "SWcursor" "on"
Option "NoAccel" "on"
# Option "Dac6Bit" "off"
# Option "VideoKey" ""
# Option "Display" "CRT"
Option "UseFBDev" "on"
# Option "VGAAccess" "off"
EndSection
Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
HorizSync 59-61
VertRefresh 75-117
EndSection
Section "Screen"
Identifier "Default Screen"
Device "ATI Technologies Inc Rage 128 RL/VR AGP"
Monitor "Generic Monitor"
DefaultDepth 24
SubSection "Display"
Depth 1
Modes "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 4
Modes "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 8
Modes "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 15
Modes "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 16
Modes "1024x768" "800x600"
EndSubSection
SubSection "Display"
Depth 24
Modes "1024x768" "800x600"
EndSubSection
EndSection

That’s it!