1

I need some hints because of my 3 screen setup:

I have an Lenovo X240 with ultradock, which supports displaying to 3 screens. But my external screens are recognized as one generic screen. See my actual xrandr query output:

xrandr -q

Screen 0: minimum 320 x 200, current 3840 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 276mm x 156mm
   1920x1080      60.0*+   59.9  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1280x1024      60.0  
   1440x900       59.9  
   1280x960       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 521mm x 293mm
   1920x1080      60.0*+   59.9  
   3840x1080      60.0  
   2560x1024      60.0  
   1680x1050      60.0  
   1280x1024      75.0     60.0  
   1440x900       59.9  
   1280x960       60.0  
   1280x800       59.8  
   1152x864       75.0  
   1280x720       60.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        75.0     66.7     60.0     59.9  
   720x400        70.1  
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

First one is my Laptop-screen. The other 2 screen are attached by Displayport and HDMI. This setup works on windows, so the hardware should not be a problem.

I'm using Ubuntu 14.04.1 LTS with stock 3.13.0-44 and default intel graphic driver from the distribution. Has anybody an idea how to debug this problem?

My Windows-setup is here.

1 Answer 1

1

The problem exists because my ubuntu 14.04.1 does not support DisplayPort Multi Stream Transport. Ubuntu 14.10 will have the same problem also.

Its possible it is working on 14.04.2. Release notes just looking fine, not tested.

This functionality is added in the following kernel 3.17 and intel display-driver: (link deleted because of missing reputation points. - But links can be found in the bugreport below)

it works on Ubuntu 15.04 Alpha 2 straight out of the box, on Ubuntu 14.10 you need just a newer Kernel. at least kernel 3.17.

I recommend to upgrade to ubuntu 14.10, and then install kernel 3.17. An example instruction: http://ubuntuhandbook.org/index.php/2014/11/how-to-upgrade-to-linux-kernel-3-17-4-in-ubuntu-14-10/

here is a nice description about this problem: http://cweiske.de/tagebuch/thinkpad-ultradock-screens.htm

Bugreport for ubuntu could be found here: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1104230

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .