Greetings. This is both a review, and a question.
First the review. I know that the Plugable Triple Display USB-C docking station (UD-ULTC4K) is not officially supported for Linux. However I thought I would give it a try anyway. I’m pleased to report that, by and large, it DOES work with Ubuntu 16.04, WITH three external monitors.
My laptap specs are: Dell Precision 5520, with Xeon processor, and Intel HD and Nvidia GPUs, 4K touch sensitive screen.
OS: Xubuntu 16.04.3 LTS
External monitors: Three 1920x1080 HD widescreen Asus monitors, with HDMI and DVI connectors.
What worked right out of the box:
- All USB peripherals, including USB3 external SATA hard drive, Logitech K800 keyboard and M705 mouse (both using a single Logitech Unifying USB receiver), flash drive, etc.
- Ethernet adapter.
- External monitor connected to HDMI port.
What needed a little work:
The other two monitors are connected to the DisplayLink ports using two Plugable DisplayPort to HDMI Passive Adapters. Those did work after I installed the latest Linux driver available from displaylink.com.
The display on all three monitors was a little unreliable, requiring me to re-do the configuration after each reboot, and occasionally having unplug the dock, reboot, get the single monitor working again, plug the dock back in, etc. I finally found the problem was with the xorg hwe hardware stack. When I removed all the xserver-xorg…hwe packages and re-installed the older (non-hwe) xorg packages, things got a lot more stable. Reboots still occasionally fail to start a monitor, or maintain my arrangement, but from what I read that’s a common problem with Linux with multiple monitors. I fixed that by writing a short script using xrandr to reset my configuration after rebooting.
However, now we’re down to what doesn’t work. Basically there seems to be an upper limit to how many devices I can plug into this dock, and the limit is rather small. When I tried to attach my external Logitech C190 webcam, it would not fully function. The kern.log was full of messages saying, “Not enough bandwidth for new device state.” When I plugged the webcam into another USB port directly on the laptop, it worked just fine. It only fails with I plug it into the dock.
I’ve read other reports online that older USB peripherals will use too much bandwidth when plugged into USB3 docks. Is that what is going on here? If I only plugged USB3 devices into the dock, should I be able to attach more devices? (The keyboard/mouse receiver and webcam are both USB-2 devices.)
Right now the only things connected to the dock are the monitors, the Unifying receiver for the keyboard/mouse, and the wire to the external speakers. That’s not much. Adding anything else seems to overload the available USB bandwidth.
Overall I’m very happy with the dock. My major concern with moving from a desktop to a laptop as my primary machine was being able to support my three external monitors. If it does nothing else, the dock is worth it for providing that. (Note, this are only 1920x1080 monitors. I have yet to test adding three 4k monitors, since I don’t have any yet.) Still, I would love to be able to connect *everything* into the dock, and only have one thing to unplug when I want to take the laptop with me.
LB (Seattle, WA)