Ubuntu 14.04 Dell E7240 - Docked - doesn't recognize second monitor

Question

I have the same problem as the post below.

Ubuntu 14.04 and Dell Latitude E5540 Multiple Monitors not working

System:    Dell E7240
Video:     Intel Haswell
Dock:      Dell
Monitors:  2 x DVI Dell 19in Wide

The screens are on and both get a signal. One monitor replicates the other. It seems that Ubuntu doesn't recognize that their are 2 monitors.

Any help with how to resolve this would be much appreciated. Thx

lspci | grep VGA

00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 0b)

xrandr --query

Screen 0: minimum 8 x 8, current 1440 x 900, maximum 32767 x 32767
eDP1 connected (normal left inverted right x axis y axis)
   1366x768       60.0 +   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 1440x900+0+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900       59.9*+   75.0  
   2560x1024      60.0  
   2880x900       60.0  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        72.2     75.0     60.3     56.2  
   640x480        75.0     72.8     66.7     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)

---

Solution 1

• The Dell E7240 integrates a DisplayPort MST (Multi Stream Transport) hub which enables multiple monitors to be used through a single DisplayPort interface. Unfortunately Linux does not support DisplayPort MST yet. See freedesktop.org bug #72795 - Dell dock DVI knocks out DP when unplugged.

• There are firmware bugs in the Synaptics VMM2320 MST hub that is integrated in the Latitude E5440/E5540/E7240/E7440. Make sure you upgrade to the latest firmware, see Dell support for details (2.15,A01 12/23/2013 is the latest I could find)

Solution 2

This might be a well known problem according to the Dell-Website (http://www.dell.com/support/article/us/en/19/SLN288845/EN):

Multiple external display issues when docked with a Latitude E7440 or E7240 portable system

• External displays fail to detect during system power on while docked.
• External displays may flicker.
• Various screen resolution and graphic profile retention issues.
• External displays may black out or go to power save mode after extended time.
• No video on external displays prior to the loading of the operating system.

Dell recommends to update the BIOS for the models Lattitude E7440/E7240 to fix this problem. If that doesn't help it is recommended to install the newest graphics driver and synaptics firmware from the Dell driver database.

Solution 3

Dual displays can be enabled quite easily. I have that same Dell e7240 with 2 displays up an running via dock.

Please see my answer https://askubuntu.com/a/552094/349788

Comments

[Learning]

haven't actually had time to test this, but this might be a solution to the problem, askubuntu.com/a/499010 I am having the same problem with my work DELL E7240 docked, and dual monitors connected to the dock, the screen is just mirrored. Planning to try if i'll get something out of the tip in the linked post, i'll hopefully come back and share the result. Sinc Kalle

[Fabby]

Although your answer is 100% correct, it might also become 100% useless if that link is moved, changed, merged into another one or the main site just disappears... :-( Therefore, please edit your answer, and copy the relevant steps from the link into your answer, thereby guaranteeing your answer for 100% of the lifetime of this site! ;-) You can always leave the link in at the bottom of your answer as a source for your material...

[Cord Kaldemeyer]

I have updated my answer :)

[Fabby]

Well done! Upvoted! (though why someone would downvote without leaving a comment is beyond me...) :-(