e7440 Latitude / Dell Dock + Dual Monitors + Ubuntu 14.04 [FIXED]

Since I was pulling my hair out over getting a multi-monitor setup to work properly, I figured I'd [hopefully] save someone else the same grief. This allows both monitors to function properly (extended mode -- NOT mirror mode), without having to split connections (e.g., 1 DVI + 1 HDMI, etc). Although not ideal, splitting the connections across DVI (dock) & HDMI port (laptop) did function in extended mode previously. The following restores dual DVI connections via the ePort dock.

 

OS: Ubuntu 14.04 LTS

System: Dell Latitude e7440 (Intel HD Graphics 4400)

Dock: Dell ePort Replicator Plus

Monitors: x2 Dell U2412M; via x2 DVI connectors (on ePort Plus dock)

 

NOTE: Just incase there's any 'n00bz' here, I'm going to give easy to follow instructions. Most regular users (everyone here) can bypass the nitty-gritty steps, and tailor it your own way. 

 

1. Download/Install 'drm-i915-mst-support' kernel branch - Compile a copy of Dave's MST support branch.
   1. wget http://cgit.freedesktop.org/~airlied/linux/snapshot/linux-drm-i915-mst-s...
   2. tar xzvf linux-drm-i915-mst-support.tar.gz
   3. cd linux-drm-i915-mst-support
   4. sudo make-kpkg -j 4 --initrd --append-to-version=mstSupportKernel kernel-image kernel-headers
   5. Answer all the kernel configuration questions. You can probably hit enter for almost, if not all, of them. On my end, the 'i915' module support was added automatically.
   6. Once the build is complete, you should have two DEB packages in the parent directory of "linux-drm-i915-mst-support". Install those two kernel packages.
   7. sudo dpkg -i ../linux*mstSupportKernel*.deb
      
       
2. ​Download/Install xserver-xorg-video-intel_2.99.912
   1. wget http://ppa.launchpad.net/xorg-edgers/ppa/ubuntu/pool/main/x/xserver-xorg...
   2. sudo dpkg -i xserver-xorg-video-intel_2.99.912+git20140710.8587b2ff-0ubuntu0sarvatt~trusty_amd64.deb

At this point, you should be able to reboot and select "Advanced" from GRUB boot menu. Select and boot the new kernel that was compiled (e.g., 'mstSupportKernel'). You should be good to go now, and configure your displays as normal (System Settings > Display). Be sure to check that display "mirroring" isn't enabled though.

However, incase you have any issues (screens don't turn on, etc.), read the notes below.

Important Notes:

1. I tried many/multiple kernels but didn't have any luck until updating to 2.99.912 userspace as well.
    
2. On my end, my monitors didn't come up after the reboot. When I opened the laptop's lid (while docked), I noticed an error regarding "CRTC 63" (if I recall correctly). After clicking the OK button, the error disappeared. The monitors turned on momentarily after opening the lid.
    
3. On subsequent reboots, I've noticed that if my laptop lid is open, I don't get that 'CRTC' error, and the monitors turn on properly.
    
4. I haven't begun to look into the error message upon (lid-closed) boot yet. I'll post an update once I find a resolution.

Just for grins, here's what the display setup looks like now. Previously, I only had eDP1 and DP1.

After this update, I've got eDP1, DP1, DP2 (monitor #1), and DP3 (monitor #2), and DP4.

xrandr