I've got that in progress. In the meantime, I realized there was a newer kernel+driver from yours and the xorg-edgers PPAs, so I did that upgrade, and now unity-control-center only sees one external monitor, with the second being treated as a mirror of the first. This is using: 3.16.0-28-generic xserver-xorg-video-intel 2:2.99.916+git20141210.04a09d35-0ubuntu0sarvatt
Here's some drm.debug logspam which may or may not be useful. I'm in the process of updating to the mainline 3.17 - I'll report back soon with results. ** Attachment added: "debug.txt" https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1104230/+attachment/4278747/+files/debug.txt -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xserver-xorg-video-intel in Ubuntu. https://bugs.launchpad.net/bugs/1104230 Title: DisplayPort 1.2 MST support is missing in the Intel driver Status in X.org xf86-video-intel: Unknown Status in xserver-xorg-video-intel package in Ubuntu: Confirmed Bug description: SRU Justification: Impact: Many users expect the possibility to use the DP1.2 MST feature which enables them to use a number of different display setups: daisy-chaining DP1.2 displays, some 4K displays appearing as 2 separate displays, 3D displays. This however is not supported in Ubuntu stable kernel. Fix: A series of 18 cherry-picks from v3.17 kernel backported to v3.16 by the original author of the feature: David Airlie. Regression Potential: These patches were merged upstream in v3.17 without any reported regressions. Original description: I have two recent DisplayPort monitors, both supporting the 1.2 version of the standard and one containing an MST hub (DELL 2913WM). I have an Intel Haswell based NUC connected over mini-displayport to the display containing the hub, then the second display is plugged in that one over DisplayPort. DisplayPort 1.2 is enabled on the display containing the hub and the second display lights up fine but just works as a clone of the first display, without ever showing up in xrandr, dmesg or any other useful logs I could find. My understanding of MST is that the second display should show up as DP2 on my laptop so I can configure it as I would any other display. UPDATE: Updated the bug report after it was pointed out that the original test hardware, a Lenovo x230 isn't DP 1.2 capable. The same test on hardware also fails, due to missing support for MST in the driver. To manage notifications about this bug go to: https://bugs.launchpad.net/xserver-xorg-video-intel/+bug/1104230/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
