USB-C port - is it full-featured, capable of connecting to a monitor?

Last year I backed a Kickstarter project from Desklab, called the Ultralight Portable Touchscreen Monitor, 4K. I received the monitor last week and in the FAQ I read that to use all functions, the USB-C port needs to be “full-featured” and allow the touchscreen function.

Does the USB-C port on the Librem 5 phone comply with these requirements?

Thanks for your help!


For more info, I’ll direct you to FAQ answers on these. “Full featured” isn’t a technical term, so it would help to have a clarification on that from the monitor manufacturer. As the FAQ notes, “displayPort alt-mode over USB-C” is what you’re looking for (or, what L5 provides). The other (unlikely) alternative being HDMI alt-mode, apparently.


Additionally to what @JR-Fi already provided, I unfortunately couldn’t find any spec of the USB-C port from that Desklab Screen. Even the manual doesn’t mention wether it uses Displayport Alt-Mode (Librem 5) or HDMI Alt-Mode.

Concerning the “full-featured” USB-Port, I guess they just mean that the port is capable of transmitting data (and video).

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Now that you have established that. Is there a function on the L5 to turn on the video to the port? (Is it it self-detecting or does that code have yet to be written?)

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There are videos of the L5 connected to a monitor… somewhere. It is functionality that is currently operational.


I’m fairly sure that any device with displayport alt mode out is required to automatically detect monitors whenever they’re connected.
I’m also fairly sure that it has to be displayport alt mode because I’ve read that HDMI alt mode won’t allow the use of peripherals besides the display (like a touch screen) while displayport alt mode does, and that would explain why almost every portable monitor, current lapdock, cell phone, graphics card and laptop I know of that had video in/out over USB-C uses displayport alt mode.
I wish I could prove any of that, any actual information on these particular differences is buried under a mountain of clickbait.
Anyway, here’s a librem 5 connected to a nexdock. I’d bet on, but can’t guarantee, your desklab working without having to do anything more than plug it in. Even at 4k.

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From my testing, with a different monitor, the answer is “yes but”.

Output of video via USB-C worked, input of “mouse” events from the touchscreen via USB-C worked, but …

I couldn’t meaningfully get the external monitor to replace the built-in screen or anything else useful. I concluded at the time that this functionality is not ready for prime time.

I think it probably can be made to work if you know all the right shell commands. Trying to do it from the GUI, as I was, may not work adequately at the current time. If you are super handy with shell commands and editing config files and ??? perhaps it will work for you.

(and, yes, who knows what “full featured” means but lsusb -v is your friend).

In case it matters, my display is FHD, not 4K UHD. Can you link to your product?

Up to a point, yes. Connect the external monitor and an additional monitor automatically shows up in the Settings; and a default background screen (“blue hexagons”) is automatically output to the external monitor.

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Thanks to all who answered - at least I feel better about the integration of the monitor with my Librem 5 when I get it. As soon as I do, I’ll let you know how it goes!

Many thanks again for your help!


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I’ve just tried a Dell USB-C dock and can report a good outcome.

I got the usb-port working (for a mouse right now), the ethernet and the HDMI. Convergence works (go to Devices->Display to see the arrangement, and drag one of the windows with the mouse).

The dock is small and thus very portable, but has only one USB port and does not provide power.

Hmm, after disconnecting the USB-C cable, the settings dialog still showing became unresponsible for quite a while and could not be closed during this period. After some (two?) minutes it finally worked as it should.

I gave the PINEPHONE USB-C Docking Bar a shot, but with negative outcome.

I was able to use the USB ports for the mouse and keyboard, but not for the ethernet nor the hdmi. Also, the power supply, that the dock provides, was not used. Further, the dock triggered a kernel-oops.

As i’ve seen it working relatively well with the pinephone, chances are, to get the dock going eventually.

Overall it could be well suited for a convergence configuration as it provides some power and has enough connectors and is small.