Once Ubuntu user returned after a few years messing around with other distros. I have just installed 14.04 and I'm having an issue with my dual monitors. I've Googled this issue only to find solutions for setups with dedicated graphics (Nvidia/ATI) cards.

My laptop is using integrated Intel graphics. I have two monitors attached to my docking station, but Display is not detecting the seperate screens, and they are just being mirrored.

I have tried it with DVI x 2 and DVI + VGA, with no joy. It works fine on Windows.

Any ideas? I'd like to run an extended desktop over dual monitors (as one does).

Thanks in advance.

Edit: This is the output of xrandr:

Screen 0: minimum 320 x 200, current 1920 x 1200, maximum 32767 x 32767
eDP1 connected (normal left inverted right x axis y axis)
   1366x768       60.1 +   40.0  
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 connected primary 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   3840x1200      60.0  
   2560x1024      60.0  
   1920x1080      60.0  
   1600x1200      60.0  
   1680x1050      60.0  
   1280x1024      60.0  
   1280x960       60.0  
   1024x768       60.0  
   800x600        60.3  
   640x480        60.0  
   720x400        70.1  
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis) 

1 Answer 1


The problem is that your connection to the external monitors is through a DisplayPort connection to the docking device. The dock is using a single DisplayPort connection to provide both monitors over a single channel. To do this, it is using Multi-Stream Transport (MST), which is not yet well supported in Linux and Xorg.

Until the Hardware Enablement Stack for 14.04 becomes available after 14.10 is released, you won't be able to use the feature with the standard kernel and Xorg packages.

Options until a kernel and Xorg are available via normal channels on 14.04 that include this support, are to use a PPA which contains the back-ports of the necessary versions (assuming that the hardware you have is supported in the newer versions already), or compile your own packages.

  • 1
    Thanks for that. I've tried switching out the DisplayPort - DVI adaptor for VGA, using DVI and VGA, and the problem persists. But am I missing something here?
    – R14
    Aug 7, 2014 at 21:53
  • All the video ports on the dock appear as a single DisplayPort to the laptop. It is the eDP1 in the xrandr output.
    – dobey
    Aug 7, 2014 at 21:56
  • Ok. Thank you. And advice re PPA?
    – R14
    Aug 7, 2014 at 21:57
  • Do older versions of Ubuntu support MST?
    – R14
    Aug 7, 2014 at 22:57
  • No, it's a relatively new technology and only recently has started to get real support in the upstream kernel and Xorg code bases. As far as PPAs, I don't know if there's a good one that has both the kernel and Xorg (or that it will even actually work with your hardware). There's a similar problem for 4K monitors, and I'm just using HDMI on mine for now.
    – dobey
    Aug 8, 2014 at 1:33

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