I tried with this problem
for 2 years already. LOL, today, I install Ubuntu
for I have to resolve it or I will back to stupid Windows 7.
First, I have 3 monitors. My graphic card is support dual ( ATI Radeon ), so I have no problem on extend those multi monitor on VGA and DVI.
The 3rd monitor is Displaylink USB.
After installed everything required, when I reboot, the displaylink monitor show "Ubuntu ...." like logo / loading screen.
I go to System Display , Detect monitor, it only show my 1st and 2nd, NO 3RD Displaylink.
I can move my mouse between those 1st & 2nd, but the 3rd is only show the Ubuntu Screen.
I press Ctrl+Alt+1, then screen switch to Displaylink USB 3RD monitor, but its "Terminal" not a desktop.
Then I press Ctrl+Alt+7 , the screen switch back to my 1st, 2nd, and the displaylink 3rd is witch back to Logo / Ubuntu again.
This is my /etc/X11/xorg.conf :
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "aticonfig-Screen[0]-0" 0 0
Screen 1 "DisplayLinkScreen" Leftof "aticonfig-Screen[0]-0"
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
ModulePath "/usr/lib/xorg/modules"
FontPath "/usr/share/fonts/X11/misc"
FontPath "/usr/share/fonts/X11/cyrillic"
FontPath "/usr/share/fonts/X11/100dpi/:unscaled"
FontPath "/usr/share/fonts/X11/75dpi/:unscaled"
FontPath "/usr/share/fonts/X11/Type1"
FontPath "/usr/share/fonts/X11/100dpi"
FontPath "/usr/share/fonts/X11/75dpi"
FontPath "/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
FontPath "built-ins"
EndSection
Section "Module"
Load "glx"
Load "dri2"
Load "dbe"
Load "dri"
Load "record"
Load "extmod"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5 6 7"
EndSection
Section "Monitor"
Identifier "aticonfig-Monitor[0]-0"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
EndSection
Section "Monitor"
Identifier "DisplayLinkMonitor"
EndSection
Section "Monitor"
Identifier "0-DFP1"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
Option "PreferredMode" "1680x1050"
Option "TargetRefresh" "60"
Option "Position" "0 0"
Option "Rotate" "normal"
Option "Disable" "false"
EndSection
Section "Monitor"
Identifier "0-CRT2"
Option "VendorName" "ATI Proprietary Driver"
Option "ModelName" "Generic Autodetecting Monitor"
Option "DPMS" "true"
Option "PreferredMode" "1920x1080"
Option "TargetRefresh" "60"
Option "Position" "1680 0"
Option "Rotate" "normal"
Option "Disable" "false"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "NoAccel" # [<bool>]
#Option "SWcursor" # [<bool>]
#Option "Dac6Bit" # [<bool>]
#Option "Dac8Bit" # [<bool>]
#Option "BusType" # [<str>]
#Option "CPPIOMode" # [<bool>]
#Option "CPusecTimeout" # <i>
#Option "AGPMode" # <i>
#Option "AGPFastWrite" # [<bool>]
#Option "AGPSize" # <i>
#Option "GARTSize" # <i>
#Option "RingSize" # <i>
#Option "BufferSize" # <i>
#Option "EnableDepthMoves" # [<bool>]
#Option "EnablePageFlip" # [<bool>]
#Option "NoBackBuffer" # [<bool>]
#Option "DMAForXv" # [<bool>]
#Option "FBTexPercent" # <i>
#Option "DepthBits" # <i>
#Option "PCIAPERSize" # <i>
#Option "AccelDFS" # [<bool>]
#Option "IgnoreEDID" # [<bool>]
#Option "CustomEDID" # [<str>]
#Option "DisplayPriority" # [<str>]
#Option "PanelSize" # [<str>]
#Option "ForceMinDotClock" # <freq>
#Option "ColorTiling" # [<bool>]
#Option "VideoKey" # <i>
#Option "RageTheatreCrystal" # <i>
#Option "RageTheatreTunerPort" # <i>
#Option "RageTheatreCompositePort" # <i>
#Option "RageTheatreSVideoPort" # <i>
#Option "TunerType" # <i>
#Option "RageTheatreMicrocPath" # <str>
#Option "RageTheatreMicrocType" # <str>
#Option "ScalerWidth" # <i>
#Option "RenderAccel" # [<bool>]
#Option "SubPixelOrder" # [<str>]
#Option "ClockGating" # [<bool>]
#Option "VGAAccess" # [<bool>]
#Option "ReverseDDC" # [<bool>]
#Option "LVDSProbePLL" # [<bool>]
#Option "AccelMethod" # <str>
#Option "DRI" # [<bool>]
#Option "ConnectorTable" # <str>
#Option "DefaultConnectorTable" # [<bool>]
#Option "DefaultTMDSPLL" # [<bool>]
#Option "TVDACLoadDetect" # [<bool>]
#Option "ForceTVOut" # [<bool>]
#Option "TVStandard" # <str>
#Option "IgnoreLidStatus" # [<bool>]
#Option "DefaultTVDACAdj" # [<bool>]
#Option "Int10" # [<bool>]
#Option "EXAVSync" # [<bool>]
#Option "ATOMTVOut" # [<bool>]
#Option "R4xxATOM" # [<bool>]
#Option "ForceLowPowerMode" # [<bool>]
#Option "DynamicPM" # [<bool>]
#Option "NewPLL" # [<bool>]
#Option "ZaphodHeads" # <str>
Identifier "Card0"
Driver "radeon"
BusID "PCI:5:0:0"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "ShadowFB" # [<bool>]
#Option "Rotate" # <str>
#Option "fbdev" # <str>
#Option "debug" # [<bool>]
Identifier "Card1"
Driver "fbdev"
BusID "PCI:5:0:0"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "ShadowFB" # [<bool>]
#Option "DefaultRefresh" # [<bool>]
#Option "ModeSetClearScreen" # [<bool>]
Identifier "Card2"
Driver "vesa"
BusID "PCI:5:0:0"
EndSection
Section "Device"
Identifier "aticonfig-Device[0]-0"
Driver "fglrx"
Option "Monitor-DFP1" "0-DFP1"
Option "Monitor-CRT2" "0-CRT2"
BusID "PCI:5:0:0"
EndSection
Section "Device"
Identifier "DisplayLinkDevice"
Driver "displaylink"
Option "fbdev" "/dev/fb1"
Option "ShadowFB" "off"
EndSection
Section "Screen"
Identifier "aticonfig-Screen[0]-0"
Device "aticonfig-Device[0]-0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Virtual 3600 1920
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "DisplayLinkScreen"
Device "DisplayLinkDevice"
Monitor "DisplayLinkMonitor"
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1920x1080"
EndSubSection
EndSection
