I have a Dell U2722DE with a USB-C 3.2 Gen 2 upstream/DisplayPort 1.4 (DisplayPort 1.4 mode/power up to 90W) port as my first screen in the chain.
The second screen in the chain is a Samsung S27H85QFU connected via a display port cable.
MST is turned on on the Dell monitor.
This works on some laptops but not on others. I have 4 laptops at hand:
On the X280 & L490, everything is working just fine, but on the L14 and E14, the 3rd monitor is not working.
When I say "3rd monitor not working", I mean that the Samsung monitor is recognized by the OS and even used, but doesn't show any output.
Since all of them have different OSes installed, I went the route of eliminating this difference first, but even the E14 with Windows installed exhibits this problem.
Next, I took a look at hardware (I'm a Software Dev, so not my forte).
I noticed that the L14 and E14 both have a Thunderbolt 4, whereas the X280 and L490 don't have that (I got them even before the specifications came out). First of all, I bought a Thunderbolt 4 cable to make sure it was not the cable causing this problem.
However, the cable makes no difference at all. Now I'm a bit at a loss of what else I could/should try.
