[CentOS] CentOS 5 dual head doesn't work [SOLVED}

On 5/9/07, Jeff Stacey wrote:
> A quick google turned up this
>
> http://gentoo-wiki.com/HOWTO_Dual_Monitors#With_the_proprietary_binary_driver
>
> Newer ati-drivers come with a handy aticonfig script that actually
> produces a working dual-head setup. This is the quick-and-easy way. Log
> out of X, backup your xorg.conf and run something akin to the following
> line:
>
> # aticonfig --initial=dual-head --dtop=horizontal --screen-layout=right --iagp=off -v
> # /etc/init.d/xdm restart
>

Well, I finally got it working.  I don't know how much of this I
actually needed to do, but it took this route to get the dual head to
work.

1) Recompiled and installed the kernel modules.  This was recommended
in the above wiki, but before the quoted lines, so I tried it.  Since
the right config options were already on, this was probably just a
waste of time, though semi-informative.

2) Re-ran the ati-driver-installer-8.35.5-x86.x86_64.run program.
This probably had no effect to speak of - I didn't notice any.

3) Installed the fglrx64 rpm.  This got errors (couldn't find the
fglrx module???) but it claimed to be installed, so after removing it
and reinstalling it, I left it alone.

4) Went to init level 3 and re-ran the aticonfig program.  I ran it
once with the above noted dual-head string (except for the --iagp
because it complained about that before seg faulting.  Then I ran it
with --initial only.  That seemed to go ok.  So I ran it with the
--initial=dual-head option (only).  Segmentation fault.

5) Saved the xorg.conf file and went in to edit it.  It looked liked
the below with a few fewer lines (no aticonfig[1] entries at all).  I
added all the aticonfig[1] entries where they are now, but the desktop
horizontal option was not there.

6) Rebooted.

7) X came up with mirrored desktops again.  I logged in as root and
ran system-config-display (from the gnome menu).  it said "Individual
desktops" so I changed that to "Spanning desktops").  Saved that (no
monitor or video card changes).  Then I vi'ed into the xorg.conf file
and noticed the first device had the desktop horizontal option turned
on.  Just in case, I added it to the first aticonfig[0] device, too.
Saved a copy of that, just for good measure.  Then I logged out.

8) New screen: left screen had the login box, all stretched out.
Right screen - the blue background.  I logged in as me and now I have
spanning desktops (finally) again.

Thanks to all, but mostly Jeff Stacey, who hung in there and kept
sending me occasional hints.  This time, it all fell into place.

Here is my current xorg.conf, which seems to work:

# Xorg configuration created by system-config-display

Section "ServerLayout"
        Identifier     "Multihead layout"
        Screen      0  "aticonfig-Screen[0]" 0 0
        Screen      1  "aticonfig-Screen[1]" RightOf "aticonfig-Screen[0]"
        InputDevice    "Keyboard0" "CoreKeyboard"
        Option      "Clone" "off"
        Option      "Xinerama" "on"
EndSection

Section "Files"
EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "us"
EndSection

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "ATI Proprietary Driver"
        ModelName    "Generic Autodetecting Monitor"
        Option      "DPMS" "true"
EndSection

Section "Monitor"
        Identifier   "Monitor1"
        VendorName   "Monitor Vendor"
        ModelName    "Generic Autodetecting Monitor"
 ### Comment all HorizSync and VertSync values to use DDC:
        HorizSync    0.0 - 0.0
        VertRefresh  0.0 - 0.0
        Option      "DPMS" "true"
EndSection

Section "Monitor"
        Identifier   "aticonfig-Monitor[0]"
        Option      "VendorName" "ATI Proprietary Driver"
        Option      "ModelName" "Generic Autodetecting Monitor"
        Option      "DPMS" "true"
EndSection

Section "Monitor"
        Identifier   "aticonfig-Monitor[1]"
        Option      "VendorName" "ATI Proprietary Driver"
        Option      "ModelName" "Generic Autodetecting Monitor"
        Option      "DPMS" "true"
EndSection

Section "Device"
        Identifier  "Device0"
        Driver      "vesa"
        Option      "DesktopSetup" "horizontal"
        BusID       "PCI:1:0:0"
EndSection

Section "Device"
        Identifier  "Device1"
        Driver      "vesa"
        BusID       "PCI:1:0:1"
EndSection

Section "Device"
        Identifier  "aticonfig-Device[0]"
        Driver      "fglrx"
        Option      "DesktopSetup" "horizontal"
EndSection

Section "Device"
        Identifier  "aticonfig-Device[1]"
        Driver      "fglrx"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Device0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
                Modes    "1280x1024" "1280x960" "1280x800" "1152x864" "1024x768"
 "800x600" "640x480"
        EndSubSection
EndSection

Section "Screen"
        Identifier "Screen1"
        Device     "Device1"
        Monitor    "Monitor1"
        DefaultDepth     24
        SubSection "Display"
                Depth     24
                Modes    "1280x1024" "1280x960" "1280x800" "1152x864" "1024x768"
 "800x600" "640x480"
        EndSubSection
EndSection

Section "Screen"
        Identifier "aticonfig-Screen[0]"
        Device     "aticonfig-Device[0]"
        Monitor    "aticonfig-Monitor[0]"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
        EndSubSection
EndSection

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

-- 
Mark Hull-Richter
DATAllegro (www.datallegro.com)
85 Enterprise, Second Floor, Aliso Viejo, CA  92656
949-680-3082 - Office     949-330-7691 - fax