Problems with (tiled) MST display (Dell UP3214Q)

Submitted by Paul Menzel

Assigned to Stanislav Lisovskiy

Link to original bug (#107845)

Description

Created attachment 141467
Linux 4.18.6 messages

Using the MST display Dell UP3214Q connected over DisplayPort, there are several problems, which are happening since at least 4.14 and are still present with Linux 4.18.6.

1. Restarting the system and leaving the monitor on, neither the Fujitsu firmware nor Linux is able to display something. (This happens rarely.)
   

2. Turning the monitor off and back on, sometimes the monitor does not detect a signal, and only after waiting a while and pressing keys, or turning it off and back on several times, a connection is established and an image displayed (which might have the problems below though).

3. The panel order is sometimes switched (LR becomes RL, where X and Y are panels).

4. The X server shows each panel as one screen, and does not overlap them.

5. Instead of one full screen of 3840x2160, only one screen 1920x2160 seems to be detected and stretched over the whole display.

The device below is used.

00:02.0 VGA compatible controller [0300]: Intel Corporation HD Graphics 530 [8086:1912] (rev 06)

Please find the debug log attached. In this time the aforementioned problems happened.

**Attachment 141467**, "Linux 4.18.6 messages":
linuxâ__4.18.6â__dmesg.txt