I have purchased the new 5600M in Dell's G5 15 5505 Notebook.
This Notebook has one USBC with included DP 1.4, one Mini-Displayport (also DP 1.4) and one HDMI to Connect external Monitors.
So far...now i want to connect 2 monitors to one port to optimize plug-handling. MST Hubs are a pretty good solution for this usual case.
First try: I connect a MST Hub to the USBC (using DP 1.4 about USBC, MST Hub from USBC Port to 2x HDMI Port to connect 2 monitors about HDMI) and the first problem is pushed out: My Notebook just detect one Monitor, but 2 are connected. The second keeps black screen.
The second try: I bought other MST Hub (Mini-Displayport to 2x DVI Port) and connecting it to the Mini Display Port: Same issue here, just one monitor of the two connected has been detected. The second Monitor also keeps the black screen.
Third try: Connecting the Mini-Displayport MST Hub (from second try) to my "old" MS Surface Pro 4 with Intel onboard graphics...and it works! Both monitors are detected correctly and they're still running.
I think there's an compatibility issue with AMD Mobile graphics by working with MST Hubs.
Can anybody reproduce that?
Have an Idea to solve this problem?
Is using "Eyefinitiy" possible with Mobile graphics 5600M? I can not found this in my Radeon Settings.
DisplayPort MST need to be fed from a proper DisplayPort source. USB-C does not widely support DisplayPort Alt-mode as of yet.
The Dell comes with the usual mini DisplayPort which is what you need to use to support the MST box
I have already tested it at the Mini Display Port in my second try (please exactly reading my problem desription!)
"The second try: I bought other MST Hub (Mini-Displayport to 2x DVI Port) and connecting it to the Mini Display Port: Same issue here, just one monitor of the two connected has been detected. The second Monitor also keeps the black screen."
So in my third try with MS Surface my Mini-Displayport-to-2x-DVI-MST-Hub is working very well!
Updating today to the newest AMD driver 20.7.1... same problem, not fixed: By using 2 Monitors about MST-Hub at USBC or Mini-DIsplayport one keeps black (not detected), the other is running. At MS Surface with Intel graphics it's running well with both MST-Hubs (I have git one with USBC and one with MiniDisyplayPort), the screen on both monitors is coming from MS Surface.
I think it's an driver or Bios issue?!
BIOS woes are commonplace. DP MST hardware headaches are also abundant. This is why cards are available with lots of DP headers on them.
Some retail restaurants with LCD displays along the wall use HDMI which supports longer cables but those panels are only 1920x1080. Some are now rolling out 4K which is more demanding on aggregate bandwidth.
DisplayPort to HDMI dongles are mass produced which makes those 4 port cards attractive.