Dual monitor setup: xrandr versus xorg.conf

multiple-monitorsxorg.confxrandr

Dual monitor setups on GNU/Linux are known to be great fun! After fiddling with my xorg.conf for a couple of days, I've managed to come to a point where I can get pretty much what I want (two screens next to each other, windows draggable from one screen to the other) by starting up X, and then manually calling:

xrandr --output CRT2 --right-of DFP2

I'm using RandR 1.3 because Xinerama does not work for my setup (and seems to be obsolete in a way, too).

According to this website, I should be able to achieve the same effect statically through my xorg.conf – however, I don't seem to get it working correctly.

I'm using the fglrx driver for my ATI card, GNOME 2.32.1, and here is my xorg.conf:

Section "ServerFlags"
    Option      "RandR" "on"
EndSection

Section "Device"
    Identifier  "Device"
    Driver      "fglrx"
    BusID       "PCI:1:0:0"
    Option      "Monitor-DFP2"      "Monitor0"
    Option      "Monitor-CRT2"      "Monitor1"
EndSection

Section "Monitor"
    Identifier      "Monitor0"
EndSection

Section "Monitor"
    Identifier      "Monitor1"
    Option          "RightOf"       "Monitor0"
EndSection

Section "Screen"
    Identifier      "Screen"
    Device          "Device"
    Monitor         "Monitor0"
    DefaultDepth     24
    SubSection "Display"
        Depth     24
        Modes     "1920x1080"
        Virtual   3840 1080
    EndSubSection
EndSection

To me, this looks pretty much like the setup recommended on the aforementioned website, however, I will simply get the same image in both monitors. Again, I can call xrandr afterwards to achieve the desired effect.

Any ideas how I can fix my xorg.conf?

Best Answer

You forgot a "Monitor" entry in the Screen section.

See below:

Section "Device"
        Identifier     "nvidia"
        Driver "nouveau"
        Option "Monitor-DVI-D-0" "samsung"
        Option "Monitor-VGA-1" "acer"
EndSection


Section "Monitor"
          Identifier   "samsung"
        Option "PreferredMode" "1280x1024_60.00"
EndSection


Section "Monitor"
          Identifier   "acer"
        Option "PreferredMode" "1280x1024_60.00"
          Option "RightOf" "samsung"
EndSection

Section "Screen"
    Identifier "screen1"
   Monitor "samsung"
    DefaultDepth 24
      SubSection "Display"
       Depth      24
       Virtual 2560 2048
      EndSubSection
    Device "nvidia"
EndSection

Section "ServerLayout"
    Identifier "layout1"
    Screen "screen1"
EndSection
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