Ubuntu – Two X-screens, how to get a window manager on second screen

multiple-monitorsunitywindow-managerxorg

I'm using Ubuntu 14.04 with Unity. I have two X-screens, on separate graphics cards. I believe the screens are :0.0 and :0.1.

The problem is that, at startup, only my primary screen has a window manager, with Unity/compiz on it.

I have tried the following:

DISPLAY=:0.1 compiz --replace &

which has the effect of removing all window decorations from my primary display and removes the unity launcher. Furthermore, all keyboard input is directed permanently to my second display!

DISPLAY=:0.0 metacity --replace &

In the second display is able to restore functionality, with both displays operational, but no Unity, and no window decorations on second display.

I've tried several combinations of :0.0, :0.1, unity metacity gnome-wm and compiz with --replace, but haven't found any way to work it. What I need, is both displays to have a window manager, and to have Compositing to enabled on the primary display.

PS:

I have decided on 2 X-screens is because the monitors are driven by two different Nvidia graphics cards, so from what I gather compositing would require separate X-screens.

I have previously had success with gnome-classic + Xinerama, which allows a single large X-screen covering both monitors but with no compositing.

PS

My /etc/X11/xorg.conf has:

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 1920 0
    Screen      1  "Screen1" LeftOf "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "0"
EndSection

And

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "metamodes" "DVI-I-1: nvidia-auto-select +1080+0 {rotation=left}"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Screen"
    Identifier     "Screen1"
    Device         "Device1"
    Monitor        "Monitor1"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "metamodes" "nvidia-auto-select +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Where Device0 is a "Quadro FX 580" and Device1 is a "GeForce 8600 GT".

Best Answer

I do not think you can run the same window manager at the same time, on the same user, on two X servers. At least you can't do it with most feature-rich wms.

Try running xfwm4 (XFCE window manager) as your secondary wm.

PS: I remember having fun with a compositing enabled Xinerama on a dual card ATI config and xmonad in the past, so I would advice keeping experimenting with that if you are using >=3 monitors.

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