UD-6950 4K USB 3 with 2 monitors via KVM. 2nd monitor recently intermittent.


I am connecting to 2 Asus PB328Q monitors (2k) via a TAA compliant IOGear GCS1644 dual monitor DVI KVM. Only thing “odd” is that I use active DisplayPort to DVI adapters (GDPDVI4KA). This works fine with my other PCs. But on HP ZBook 15 3G laptop connecting via a UD-6950 4K docking station, the 2nd monitor has started to periodically connect and disconnect - seemingly at random. It worked fine until yesterday. Not sure what changed.

When I have the problem, Display Settings only show one monitor and the laptop screen. When I don’t, both monitors and the laptop screen show up.

Running Win10 Pro 64bit 1607, I’ve upgraded my nVidia driver to latest on HP site and the DisplayLink to 8.5 M1.

Today, trying something different, I turned off the laptop screen in Display Settings. After about 15-20 minutes, the screens flickered and all 3 screens were active with the “proper” screen order as I had set last week.

Yesterday, I downloaded and ran PlugDebug. The output on monitors was: Intel® HD Graphics 530, DisplayLink USB Device \.\DISPLAY8. Today, I ran when all were active and have Intel® HD Graphics 530, DisplayLink USB Device \.\DISPLAY8, DisplayLink USB Device \.\DISPLAY9. File sizes of the zip files changed from 2603kb to 3273kb.

Not sure where to look. Only thing I have not exhaustively tried is cable swapping. Although I have done some. Any advice would be appreciated.


Hello Scott,

Thank you for contacting Plugable Support and I will be happy to help.

Just to clarify your setup, you are connecting our UD-6950 docking station to the USB port on the IOGear KVM switch and you notice that the video connection to the monitors connected to our dock is recycling when using the HP ZBook, but you do not see this with other computers you have with this setup?

Pending that confirmation, it may be worthwhile to reinstall the DisplayLink drivers and run the DisplayLink cleaner utility to make sure that the software used by our dock is in a good state on the HP ZBook. To do so, please follow these steps:

  1. Disconnect the dock from the system and please remove the power cable from the dock so it turns off completely (this is important so the unit resets). Please keep it disconnected until the last step.
  2. Uninstall any and all software with ‘DisplayLink’ in the title that is present from within the Control Panel -> Programs and Features. Don’t worry if these entries are not present or if the process does not work, just move onto the next step
  3. Download, extract and run the DisplayLink cleaner tool, found here --> https://s3.amazonaws.com/plugable/bin…
  4. Once the Cleaner has been run, reboot (even if not prompted to)
  5. Now download and install the 8.5 M1 DisplayLink software, found here --> http://www.displaylink.com/downloads/…
  6. Reattach the power cable to the dock first. Once the dock is powered on, reconnect it to your system which will trigger the final portion of the installation

Thank you,

David W.
Plugable Technologies


I stepped through this entire process, above, and also made sure that I was fully up to date on HP patches. The first day, everything was “better” but not 100% addressed. Instead of 15-30 seconds of video on the second monitor with hours of none, I ended up with hours of video with 15-30 second flashes of none. Overnight, my PC was powered off by the power saving feature of windows. When I powered back on, it returned to the pattern from before. At this point, Monitor 2 is essentially dark all the time.


Hello Scott, thanks for the reply. Does the dock work properly if it is connected to the HP ZBook without the KVM in the equation? This will help further isolate the behavior.

Does disabling USB selective suspend help with the connection stability? Here’s a guide for turning this setting off within the Windows Power settings --> https://www.tenforums.com/tutorials/7…

Thank you,

David W.
Plugable Technologies


Seems identical behavior with KVM and without. (Takes a bit of time to build up enough info to validate but I think this is the case.)

One thing I recently noticed through my trial/error process is that when I turn on my wifi that both monitors seem to work OK, only very rarely having the issue. When wifi is off, the problem occurs regularly. I’m wondering if it is some sort of data volume issue through the USB 3 port.


Hi Scott, thanks for the updates and certainly strange behavior you mention regarding the stability when WiFi is turned on. Do you also unplug the Ethernet cable from the dock when this was tested?

Would it be safe to assume the disabling USB selective suspend did not help?

Thank you,

David W.
Plugable Technologies