XF86Config / Xinerama problem with X6.9

[Paul Kaplan]

I have a Thinkpad T40 (2575) with a Radeon M7 7500 video card.  It is 
connected to a Sony X93 external LCD monitor.

With Mandrake 9.2, 10.0, and 10.1 using the mandriva supplied radeon driver 
and running XFree and more recently XOrg through verson 6.8.2, the XF86Config 
file shown below allowed me to work with a single virtual desktop spanning 
the internal and external LCDs (2308x1024) using Xinerama.

I recently upgraded to Mandriva 2006 which uses a recent cvs version of XOrg 
6.9.  The virtual desktop remains, but no signal is being sent to the 
external monitor and as a result I can only see the left portion of the 
virtual desktop on the internal LCD.  The problem isn't fixed by cycling 
through the internal/external/both monitor signal (Fn+F7) setting.  
Inactivating Xinerama doesn't change things, but changing the BusID of the 
Device Videocard1 allows a single 1024x768 image to be displayed on one the 
other or both montiors.

Can anyone explain why the change in behavior and suggest a way to fix?  I am 
addicted to using the expansive virtual monitor and am lost without it.
TIA
Paul
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#Dual headed XF86Config for IBM Thinkpad T40-257551U
#Radeon M7 7500
#Works for XFree 4.3, X.org 6.7 and 6.8
#Rename file as necessary for distribution
#originally from Diego Zamboni / linux-thinkpad list

#Section "ServerLayout"
#        Identifier     "Default Layout" 
#       Screen      0  "Screen0" 0 0
#       InputDevice    "Mouse0" "CorePointer"
#       InputDevice    "Keyboard0" "CoreKeyboard"
#       InputDevice    "DevInputMice" "AlwaysCore"
#EndSection

#Section "ServerLayout"
#        Identifier     "Singlehead" 
#       Screen      0  "Screen0" 0 0
#        Screen         "Screen0"
#        Screen         "Screen1" RightOf "Screen0"
#       InputDevice    "Mouse0" "CorePointer"
#       InputDevice    "Keyboard0" "CoreKeyboard"
#       InputDevice    "DevInputMice" "AlwaysCore"
#EndSection

Section "ServerLayout"
        Identifier     "Multihead"
#       Screen      0  "Screen0" 0 0
        Screen         "Screen0"
        Screen         "Screen1" RightOf "Screen0"
        Option         "Xinerama" "true"
        InputDevice    "Mouse0" "CorePointer"
        InputDevice    "Keyboard0" "CoreKeyboard"
        InputDevice    "DevInputMice" "AlwaysCore"
EndSection

Section "Files"
    # Multiple FontPath entries are allowed (they are concatenated together)
    # By default, Mandrake 6.0 and later now use a font server independent of
    # the X server to render fonts.
    FontPath "unix/:-1"
EndSection

Section "Module"
        Load  "dbe"
        Load  "extmod"
        Load  "fbdevhw"
        Load  "glx"
        Load  "record"
        Load  "freetype"
        Load  "type1"
#       Load  "dri"
EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "keyboard"
        Option      "XkbRules" "xfree86"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "us"
EndSection

Section "InputDevice"
        Identifier  "Mouse0"
        Driver      "mouse"
        Option      "Protocol" "PS/2"
        Option      "Device" "/dev/psaux"
        Option      "ZAxisMapping" "4 5"
        Option      "Emulate3Buttons" "yes"
EndSection

Section "InputDevice"
# If the normal CorePointer mouse is not a USB mouse then
# this input device can be used in AlwaysCore mode to let you
# also use USB mice at the same time.
        Identifier  "DevInputMice"
        Driver      "mouse"
        Option      "Protocol" "IMPS/2"
        Option      "Device" "/dev/input/mice"
        Option      "ZAxisMapping" "4 5"
        Option      "Emulate3Buttons" "yes"
EndSection

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Unprobed Monitor"
#       HorizSync    31.5 - 48.5
#       VertRefresh  40.0 - 70.0
        Option      "dpms"
EndSection

Section "Monitor"
        Identifier   "Monitor1"
        VendorName   "Monitor Vendor"
        ModelName    "Unprobed Monitor"
#       HorizSync    31.5 - 67.0
#       VertRefresh  50.0 - 75.0
        Option      "dpms"
#        Modeline     "1280x1024" 135.00 1280 1308 1412 1676 1024 1027 1030 
1056
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "radeon"
        VendorName  "Videocard vendor"
        BoardName   "ATI Radeon Mobility M7"
#       VideoRam    32768
        Screen      0
        BusID       "PCI:1:0:0"
EndSection

Section "Device"
        Identifier  "Videocard1"
        Driver      "radeon"
        VendorName  "Videocard vendor"
        BoardName   "ATI Radeon Mobility M7"
#       VideoRam    32768
        Screen      1
        BusID       "PCI:1:0:0"
EndSection

Section "Screen"
#       This is the internal LCD display  
        Identifier "Screen0"
        Device     "Videocard0"
        Monitor    "Monitor0"
        DefaultDepth     24
        SubSection "Display"
                Depth     24
                Modes    "1024x768" "800x600"
        EndSubSection
EndSection

Section "Screen"
#       This is an external monitor running 1280x1024 
        Identifier "Screen1"
        Device     "Videocard1"
        Monitor    "Monitor1"
        DefaultDepth     24
        SubSection "Display"
                Depth     24
                Modes    "1280x1024"  "1024x768"
        EndSubSection
EndSection

#Section "DRI"
#       Group        0
#       Mode         0666
#EndSection
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