Redhat 5.6 双显示器 xorg.conf 设置

笔者工作站为DELL T7600，两个显示器1920*1200.配置成双屏扩展模式。使用中出现问题：用户模式下，只能一个屏幕显示。Nvidia-settings设置中，第二个屏幕为off。手动修改启用，并保存到xorg.conf，提示无修改权限。但是在其他用户下，双屏可以正常显示。
解决方案：修改xorg.conf
要点：serverLayout中设置成双头显示，默认的显示器为screen0，添加的screen1 要给出定义。还有 monitor0，monitor1.videocard0，videocard1.“1”语句复制“0”的即可。配置之后，logout。如果提示无法进入桌面，会提示语句不完整。按提示的错误信息进行更改。
#gedit /etc/X11/xorg.conf
以下为配置文件内容：
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 310.32 (buildmeister@swio-display-x86-rhel47-01) Mon Jan 14 15:51:37 PST 2013

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 310.32 (buildmeister@swio-display-x86-rhel47-01) Mon Jan 14 15:51:51 PST 2013
# Xorg configuration created by system-config-display

Section "ServerLayout"
Identifier "Multihead layout"
Screen 0 "Screen0" LeftOf "Screen1"
Screen 1 "Screen1" 0 0
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
Option "Xinerama" "on"
Option "Clone" "off"
EndSection

Section "InputDevice"

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

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

Section "Monitor"

### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
Identifier "Monitor0"
VendorName "Unknown"
ModelName "DELL U2412M"
HorizSync 30.0 - 83.0
VertRefresh 50.0 - 61.0
EndSection

Section "Monitor"

### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
Identifier "Monitor1"
VendorName "Unknown"
ModelName "DELL U2412M"
HorizSync 30.0 - 83.0
VertRefresh 50.0 - 61.0
EndSection

Section "Device"
Identifier "Videocard0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro 2000"
#Option "NoTwinViewXineramaInfo" "True"
EndSection


Section "Device"
Identifier "Videocard1"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "Quadro 2000"
#Option "NoTwinViewXineramaInfo" "True"
EndSection

Section "Screen"

Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
Option "Stereo" "0"
Option "metamodes" "DFP-0: nvidia-auto-select +0+0, DFP-2: nvidia-auto-select +1920+0; DFP-0: nvidia-auto-select +0+0, DFP-2: nvidia-auto-select +1920+0; DFP-0: 1920x1200 +0+0, DFP-2: nvidia-auto-select +1920+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection

Section "Screen"

Identifier "Screen1"
Device "Videocard0"
Monitor "Monitor1"
DefaultDepth 24
Option "Stereo" "0"
Option "metamodes" "DFP-0: nvidia-auto-select +0+0, DFP-2: nvidia-auto-select +1920+0; DFP-0: nvidia-auto-select +0+0, DFP-2: nvidia-auto-select +1920+0; DFP-0: 1920x1200 +0+0, DFP-2: nvidia-auto-select +1920+0"
SubSection "Display"
Depth 24
EndSubSection
EndSection