Triple monitor, one card; xrandr => xorg.conf

[Nick Urbanik]

Dear Folks,

It is trivially easy to set up three monitors with an ATI 5450 video
card.  One is plugged into the VGA, the other into the DVI, and the
last into the DisplayPort connector.

Now I want the display port monitor in the middle, as it is the most
fabulous.

This is easy with xrandr:
xrandr --output DVI-0 --mode 1920x1200 --output DisplayPort-0 --mode
1920x1200 --right-of DVI-0 --output VGA-0 --mode 1600x1200 --right-of
DisplayPort-0

which works like a charm.

Now trying to write that as xorg.conf.  Miserable failure.  And Gnome
3 is unable to start.

So here is the xorg.conf I have tried so far:

Section "Device"
   Identifier "ati-5450"
   Option "Monitor-DVI-0" "left"
   Option "Monitor-DisplayPort-0" "middle"
   Option "Monitor-VGA-0" "right"
EndSection

Section "Monitor"
   Identifier "left"
EndSection

Section "Monitor"
   Identifier "middle"
   Option "RightOf" "left"
EndSection

Section "Monitor"
   Identifier "right"
   Option "RightOf" "middle"
EndSection

and here is the output of xrandr:
$ xrandr
Screen 0: minimum 320 x 200, current 5440 x 1200, maximum 8192 x 8192
DisplayPort-0 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
    1920x1200      60.0*+
    1920x1080      60.0  
    1600x1200      60.0  
    1680x1050      60.0  
    1280x1024      60.0  
    1280x960       60.0  
    1024x768       60.0  
    800x600        60.3  
    640x480        60.0  
    720x400        70.1  
DVI-0 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
    1920x1200      60.0*+
    1920x1080      50.0     60.0  
    1600x1200      60.0  
    1680x1050      59.9  
    1280x1024      60.0  
    1440x900       59.9  
    1280x960       60.0  
    1280x800       59.9  
    1280x720       50.0     60.0  
    1024x768       60.0  
    800x600        60.3     56.2  
    720x576        50.0  
    720x480        59.9  
    640x480        60.0  
VGA-0 connected 1600x1200+3840+0 (normal left inverted right x axis y axis) 408mm x 306mm
    1600x1200      60.0*+
    1280x1024      75.0     60.0  
    1280x960       60.0  
    1152x864       75.0  
    1024x768       75.1     70.1     60.0  
    832x624        74.6  
    800x600        72.2     75.0     60.3     56.2  
    640x480        72.8     75.0     66.7     60.0  
    720x400        70.1  

Any suggestions on how to make a working xorg.conf?

Fedora 18 x86_64:
xorg-x11-server-Xorg-1.13.3-3.fc18.x86_64
xorg-x11-drv-ati-7.0.0-0.9.20121015gitbd9e2c064.fc18.x86_64
$ xrandr --version
xrandr program version       1.4.0
Server reports RandR version 1.4
-- 
Nick Urbanik             http://nicku.org           nicku at nicku.org
GPG: 7FFA CDC7 5A77 0558 DC7A 790A 16DF EC5B BB9D 2C24 ID: BB9D2C24