ubuntu 11.04 配置双显示器

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 270.29  (buildd@roseapple)  Fri Feb 25 14:43:24 UTC 2011

Section "ServerLayout"
Identifier     "Layout0"
Screen      0  "Screen0" 0 0
InputDevice    "Keyboard0" "CoreKeyboard"
InputDevice    "Mouse0" "CorePointer"
Option         "Xinerama" "0"
EndSection

Section "Files"
EndSection

Section "InputDevice"

# generated from default
Identifier     "Mouse0"
Driver         "mouse"
Option         "Protocol" "auto"
Option         "Device" "/dev/psaux"
Option         "Emulate3Buttons" "no"
Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

# generated from default
Identifier     "Keyboard0"
Driver         "kbd"
EndSection

Section "Monitor"

# HorizSync source: edid, VertRefresh source: edid
Identifier     "Monitor0"
VendorName     "Unknown"
ModelName      "DELL E170S"
HorizSync       30.0 - 81.0
VertRefresh     56.0 - 76.0
Option         "DPMS"
EndSection

Section "Device"
Option "TwinView" "on"
Option "MetaModes" "1280x1024,1280x1024"
Option "SecondMonitorHorizSync" "28-80"
Option "SecondMonitorVertRefresh" "43-60"
Option "TwinViewOrientation" "RightOf"
Identifier     "Device0"
Driver         "nvidia"
VendorName     "NVIDIA Corporation"
BoardName      "GeForce 9300 GS"
EndSection

Section "Screen"

# Removed Option "TwinViewXineramaInfoOrder" "CRT-1"
Identifier     "Screen0"
Device         "Device0"
Monitor        "Monitor0"
DefaultDepth    24
Option         "TwinView" "1"
Option         "TwinViewXineramaInfoOrder" "CRT-0"
Option         "metamodes" "CRT-0: nvidia-auto-select +0+0, CRT-1: nvidia-auto-select +1280+0"
SubSection     "Display"
Depth       24
EndSubSection
EndSection

关键是：
在Device 段，加入如下内容：

Option "TwinView" "on"
Option "MetaModes" "1280x1024,1280x768"
Option "SecondMonitorHorizSync" "28-80"
Option "SecondMonitorVertRefresh" "43-60"
Option "TwinViewOrientation" "RightOf"

配置好后执行如下的命令：
按alt + ctrl + f1 ，切换文本工作区
执行：

sudo /etc/init.d/gdm stop
sudo /etc/init.d/gdm start