Thanks to gwydion

I got my xorg.conf to finally work in Ubunutu 9.04 Jaunty. I was having problems where when I boot into ubuntu, I didn’t even get a login screen, it just froze at a black screen after boot up with a few artifacts of color here and there.

Took many, many hours trying to finding this solution. I ended up being able to use the proprietary driver fglrx when all was said and done, instead of having to use vesa.

Here is what I did:

dpkg-reconfigure xserver-xorg
aticonfig --initial -f --adapter=all
aticonfig --cfa --adapater=all
aticonfig --add-pairmode=<your width>x<your height>+<your width 2>x<your height 2>

Also had to add

Option "EnableRandR12" "false"

to each device section and

EnableRandR12=Sfalse

to the [AMDPCSROOT/SYSTEM/DDX] section of /etc/ati/amdpcsdb (source) in order to disable RandR 1.2

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.
#
# Note that some configuration settings that could be done previously
# in this file, now are automatically configured by the server and settings
# here are ignored.
#
# 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 "ServerLayout"
	Identifier     "aticonfig Layout"
	Screen      0  "aticonfig-Screen[0]-0" 0 0
	Screen         "aticonfig-Screen[1]-0"# RightOf "aticonfig-Screen[0]-0"
EndSection

Section "Files"
EndSection

Section "Module"
EndSection

Section "Monitor"
	Identifier   "aticonfig-Monitor[0]-0"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
	HorizSync   30-82
	VertRefresh  56-76
EndSection

Section "Monitor"
	Identifier   "aticonfig-Monitor[1]-0"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
	HorizSync   30-82
	VertRefresh  50-75
EndSection

Section "Device"
	Identifier  "aticonfig-Device[0]-0"
	Driver      "fglrx"
	Option	    "EnableRandR12" "false"
	Option	    "PairModes" "1680x1050+1280x1024"
	BusID       "PCI:3:0:0"
	Option          "XAANoOffscreenPixmaps"
EndSection

Section "Device"
	Identifier  "aticonfig-Device[1]-0"
	Driver      "fglrx"
	Option	    "EnableRandR12" "false"
	BusID       "PCI:4:0:0"
	Option          "XAANoOffscreenPixmaps"
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[0]-0"
	Device     "aticonfig-Device[0]-0"
	Monitor    "aticonfig-Monitor[0]-0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
		Modes      "1680x1050_75.00"
	EndSubSection
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[1]-0"
	Device     "aticonfig-Device[1]-0"
	Monitor    "aticonfig-Monitor[1]-0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
		Modes      "1280x1024_75.00"
	EndSubSection
EndSection

This probably is a solution for the 4870 X2, or any other X2 based board.