我安装了 Ubuntu 15.04，但我的 2 个显示器出现了问题。
我需要将我的左显示器设置为主显示器，然后才能显示登录屏幕，因为登录屏幕显示在右显示器上。我找到了一些解决方案。但是：
- 15.04 不支持 ati 驱动程序。
- xprofile 不工作。
- lightdm.conf 脚本不起作用。
- 缺少 xorg.conf。
我生成了它，但它生成了这个
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 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 "built-ins"
EndSection
Section "Module"
Load "glx"
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 "Monitor0"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
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 "Accel" # [<bool>]
#Option "SWcursor" # [<bool>]
#Option "EnablePageFlip" # [<bool>]
#Option "ColorTiling" # [<bool>]
#Option "ColorTiling2D" # [<bool>]
#Option "RenderAccel" # [<bool>]
#Option "SubPixelOrder" # [<str>]
#Option "AccelMethod" # <str>
#Option "EXAVSync" # [<bool>]
#Option "EXAPixmaps" # [<bool>]
#Option "ZaphodHeads" # <str>
#Option "EnablePageFlip" # [<bool>]
#Option "SwapbuffersWait" # [<bool>]
Identifier "Card0"
Driver "radeon"
BusID "PCI:2:0:0"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
SubSection "Display"
Viewport 0 0
Depth 1
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 4
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 8
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 15
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 16
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
它看起来好像不是完整的配置，我看到只有一个显示器，没有分辨率设置等等。
我该如何编辑它？
我的xrandr输出：
Screen 0: minimum 320 x 200, current 3040 x 900, maximum 8192 x 8192
DisplayPort-0 connected 1440x900+1600+0 (normal left inverted right x axis y axis) 408mm x 255mm
1440x900 60.0*+ 75.0
1280x1024 75.0 60.0
1280x960 60.0
1280x800 59.8
1152x864 75.0
1152x720 60.0
1024x768 75.1 60.0
832x624 74.6
800x600 75.0 60.3
640x480 75.0 60.0
720x400 70.1
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
DVI-0 connected primary 1440x900+0+0 (normal left inverted right x axis y axis) 410mm x 256mm
1440x900 59.6*+ 75.0
1280x1024 75.0 60.0
1152x864 75.0
1024x768 75.1 70.1 60.0
832x624 74.6
800x600 72.2 75.0 60.3 56.2
640x480 75.0 72.8 66.7 60.0
720x400 70.1
另外我需要将xrandr一台显示器的亮度永久设置为 0.8。这台显示器很旧，而且存在一些硬件问题，屏幕太白了。
当我通过终端设置亮度时，它看起来更好，但重启后它又恢复默认设置。有时它也会在工作时重置。