MacBuild Tips 'n Tricks

Video setup on Flower Power iMac

iMacs with 500MHz, 600MHz, and 700MHz processors, the so called Flower Power models, have a 750cx version CPU and ATI Rage 128 Pro Ultra video controller. After a normal Edgy alternate CD install, video response is extremely sluggish. For example, mouse cursor movements lag several seconds behind physical mouse movement.

A fix is suggested in http://ubuntuforums.org/showthread.php?t=191080. It consists of the following changes to /etc/X11/xorg.conf:

• in the Module section

Section "Module"
# Load "i2c"
# Load "bitmap"
# Load "ddc"
Load "dri"
Load "extmod"
Load "freetype"
Load "dbe"
Load "glx"
# Load "int10"
# Load "type1"
# Load "vbe"
EndSection

• in the Device section

Section "Device"
Identifier "ATI Technologies, Inc. Rage 128 Pro Ultra TR"
Driver "ati"
Option "UseFBDev" "false"
Option "SWcursor" "true"
Option "ForcePCIMode" "true"
Option "XAANoOffscreenPixmaps"
EndSection

The normal way to apply these changes is

1. CTL+ALT+F1 to use a virtual terminal (command line interface)
2. login as oem
3. command: sudo /etc/init.d/gdm stop
4. edit /etc/X11/xorg.conf, for example, sudo nano /etc/X11/xorg.conf
5. modify the Module and Device sections as indicated above
6. save the file and exit
7. command: sudo /etc/init.d/gdm start

The normal Ubuntu login page should appear with much better video response.

Note that the original problem is observed in Ubuntu Edgy (Release 6.10).  ATI video
driver installation is different in Ubuntu Feisty (7.04), in that a best driver version
is selected to match the detected video controller.  The problem may not be present with 
Feisty, but that has not been tested as of 15May2007.