I am a (K)ubuntu newbie, so I am still getting to grips with how the desktop environment is put together.
I am currently trying to get an MST hub to work so that I can have 3 monitors connected to my Intel NUC i3-6100U on latest Kubuntu 16.04 (Plasma).
I feel like the issues I am experiencing must be configuration issues, as it seems like (K)ubuntu - or rather Xorg, if I understand things correctly - can in certain circumstances display graphics on all 3 monitors, just not reliably.
This is the setup I am attempting:
Primary display, Asus Ve248 connected via HDMI
Two Dell 2412M displays connected via a Club3d MST Displayport Hub
All connecting cables support the "new" Displayport standard.
Symptoms:
Image will display fine, mirrored on all three displays if I just connect them up and start up the machine at login screen and if I hit CTRL+Alt+F1 to go to the terminal
Once I hit the desktop however, I get no image on the MST connected displays.
If I then go into Display Configuration and enable the two MST connected displays, usually the desktop craps out - mouse cursor, any open windows and panel moves to one of the Dell screens and I have no image on the MST connected displays.
However, I do get flashes of my desktop popping up once in a while on the MST connected displays.
After a reboot my desktop on the primary HDMI display is fine, but no image on the MST connected displays, except for intermittent flashes.
In my terminal (ctr+alt+f1) I get messages which say something like ERROR CPU Pipe B (or C) FIFO Underrun
Here's output from xrandr - not sure if it helps, but anyway:
Screen 0: minimum 8 x 8, current 5760 x 1200, maximum 32767 x 32767
DP1 disconnected (normal left inverted right x axis y axis)
DP1-1 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+
1920x1080 60.00
1600x1200 60.00
1680x1050 59.95
1280x1024 60.02
1280x960 60.00
1024x768 60.00
800x600 60.32
640x480 60.00
720x400 70.08
DP1-2 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
1920x1200 59.95*+
1920x1080 60.00
1600x1200 60.00
1680x1050 59.95
1280x1024 60.02
1280x960 60.00
1024x768 60.00
800x600 60.32
640x480 60.00
720x400 70.08
HDMI1 connected primary 1920x1080+3840+0 (normal left inverted right x axis y axis) 531mm x 299mm
1920x1080 60.00*+ 50.00 59.94 59.99
1920x1080i 60.00 50.00 59.94
1600x1200 60.00
1680x1050 59.88
1280x1024 75.02 60.02
1440x900 59.90
1280x960 60.00
1366x768 59.79
1152x864 75.00
1280x720 60.00 50.00 59.94
1024x768 75.08 70.07 60.00
832x624 74.55
800x600 72.19 75.00 60.32 56.25
720x576 50.00
720x480 60.00 59.94
640x480 75.00 72.81 66.67 60.00 59.94
720x400 70.08
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
Where should I start looking to debug this? It feels like the system is sooo close to just working right out of the box, but that there is a configuration or driver issue at work.
Any input much appreciated.
