How to get multiple displays working with docking station?

Question

I shortly installed Ubuntu on my Notebook. Standalone everything works like a charm, but if I connect it with the docking station the displays will not work like they are meant to be. So after three hours of searching and trying I need help or have to switch back to Windows.

Here is what I have:

• DELL Precision M4800 Notebook
• NVIDIA Quadro K2100M videocard
• three identical external displays, all 23''
• docking station (DELL Port Replicator)
• Ubuntu 14.04.1 LTS 64 Bit installed

I want to use two displays with DVI and the last one with VGA (because the dockingstation only have two DVI ports). One of the displays is turned upright and now there should be an extended desktop over these three external displays, the internal display can be turned off in the dockingstation.

From the DELL support page I have installed every driver that I have found, also from the NVIDIA site. Now I have "NVIDIA binary driver - version 331.113" and nvidia-settings installed. But when I try to configure the displays (either with the display settings in Ubuntu or with the installed "NVIDIA X Server Settings") the desktop will be distorted and moves around when the cursor gets to one edge.

Does anybody have a solution to solve the problem? Or a general hint in which direction I should search to get closer to a solution?

If more information are needed, feel free to ask, I will provide as many information as I can.

Solution

This affected me too. Finally after weeks of frustration I found the solution posted in a Launchpad bug (https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1382462).

In short:

1. Install CCSM (sudo apt-get install compizconfig-settings-manager)

2. In CCSM go to "General Options" --> "Display Settings" and do the following:

   • Un-check "Detect Outputs"

   • In the Outputs array, set the resolutions of each of your screens.

     In my case it was:

     1920x1080+0+0

     1920x1080+1920+0

3. Now edit your display configuration as usual. In Unity: Dash --> Screen Display

Comments

[Chessmaster]

Thanks for this solution! I can now connect two of my displays to the dockingstation and both are working. But if I try to connect the third one over VGA (because the docking station do not have any other ports free) and configure it also in CCSM it seems to be correct - until I move the mouse... When the mouse hits the border of the screen, that is connected via DVI, the hole desktop on both (DVI connected) screens is moving until I see on both screens the desktop of the (VGA connected) display. Do you have any idea to that issue?

[Chessmaster]

As mentioned from Gfish the Compizconfig Settings Manager is a big help! I configured there my three displays (and the laptop screen was possible too) and then only the problem with the moving desktop when reaching one corner was left. This could be fixed with a script called during startup invoking the xrandr command. So currently all 3 displays are working with this workaround for me, but I still use the nvidia driver. Is the display recognized if you connect just one to the VGA port?