Created attachment 131739 [details]
1st log

No user interface is present using a 4K monitor connected to a MST dongle, disabling UI TTY is present.

Configuration:

======================================
             Hardware
======================================
platform                   : SKL Canyon
motherboard id             : NUC6i7KYB
form factor                : Desktop
cpu family                 : Core i7
cpu family id              : 6
cpu information            : Intel(R) Core(TM) i7-6770HQ CPU @ 2.60GHz
gpu card                   : Intel Corporation Iris Pro Graphics 580 (rev 09) (prog-if 00 [VGA controller])
memory ram                 : 31.31 GB
max memory ram             : 32 GB
cpu thread                 : 8
cpu core                   : 4
cpu model                  : 94
cpu stepping               : 3
socket                     : Other
signature                  : Type 0, Family 6, Model 94, Stepping 3
hard drive                 : 223GiB (240GB)
current cd clock frequency : 450000 kHz
maximum cd clock frequency : 675000 kHz
displays connected         : DP-5
======================================
        Graphic drivers
======================================
modesetting                 : modesetting_drv.so
xorg-xserver                : 1.19.3
libdrm                      : 2.4.81
Aborted (core dumped)
cairo                       : 1.14.8
xserver                     : X.Org X Server 1.19.99.1
intel-gpu-tools (tag)       : intel-gpu-tools-1.18-211-g00ce341b
intel-gpu-tools (commit)    : 00ce341b

Steps to reproduce:

Connnect you DP output to a MST dongle
Connect your Dongle to your 4k monitor
Boot up


Expected result:

Normal User Interface should be up and running

Actual result: 

No UI available, monitor is not on sleep, it is jus showing black screen, no cursor.