I already posted this over at reddit, but got no response until now.

I bought this cable just to find out my system doesn't do anything. Both lsusb and tail -f /var(log/kern.log don't show any difference when plugging the cable in and out. Is it worth trying to get this to work or should I just send it back directly? What is the status of DP via USB–C in Linux? (Found a lot of rather confusing questions and answers out there)

$ lspci -d ::0c03 -k
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
    Subsystem: CLEVO/KAPOK Computer Sunrise Point-LP USB 3.0 xHCI Controller
    Kernel driver in use: xhci_hcd
01:00.0 USB controller: ASMedia Technology Inc. ASM1142 USB 3.1 Host Controller
    Subsystem: CLEVO/KAPOK Computer ASM1142 USB 3.1 Host Controller
    Kernel driver in use: xhci_hcd

OS: elementary OS 0.4.1 Loki Kernel: 4.9.18-040918-generic Hardware: Dual-Core Intel® Core™ i5-7200U CPU @ 2.50GHz Intel Corporation Device 5916 (rev 02)

  • Don't know the answer to your question, but beware of buying cables these days, and doubly so when buying video cables. Manufacturers will happily sell you cables that make no electrical sense, and "it fits" has stopped meaning "it should work" a long time ago. – Satō Katsura Nov 8 '17 at 14:51
  • USB -> monitor needs an actual chip in the converter that does the work, and a driver in the OS. – Ignacio Vazquez-Abrams Nov 8 '17 at 16:07
up vote 6 down vote accepted

Your questions are very timely, even though you asked them 7 months ago. And you asked two questions, so you get two answers:

  1. Is it worth trying to get this to work or should I just send it back directly?

A set of kernel patches to support DisplayPort over USB-C have just been published to the Linux-kernel archive here. So for the moment, you need to apply patches and roll your own kernel for it to be possibly worthwhile. (This is less scary than it might seem at first, so I hope you'll consider this encouragement and not the opposite).

A second constraint is that according to the that post in the Linux-Kernel archive, the patches are good for hardware platforms that use FUSB controllers. He will soon also publish support for UCSI controllers -- and I think (but am not positive) that both Intel and ASMedia controllers are of this type. To quote him:

I've tested these with a platform that has fusb302, and also with UCSI platforms. The UCSI driver will need separate support for alternate modes >that I'm not including to this series. I'm still working on it.

In other words, "soon."

  1. What is the status of DP via USB–C in Linux?

I learned about the above in an article in Phoronix, and the article states that the hope is to merge these patches into the 4.19 kernel.

Finally, it's worth noting that for the particular case of DisplayPort over USB-C, the cable is entirely passive and there is a rather mature standard, so you can be close to certain that your cable WILL work once there is OS support for it. This is also true of Thunderbolt over USB-C, but not true of HMDI, for example: A USB-C to HDMI cable is likely to be a DP-to-HDMI adapter on the inside, with the DP side simply using the standard USB-C connector.

If you are not going to deal with kernel patches, I would guess that your cable will 'just work' sometime between 3 months to one year from now.

  • Maybe my question might be ralated to: unix.stackexchange.com/questions/452800/display-port-via-usb-c – grafa Jul 3 at 16:18
  • Wow, thank you for your answer! Since asking I two things actually changed on my end: 1) I asked the seller for a return and refund, and they urged me to let them send me another one in case that one was just broken, despite me suggesting that my hardware wasn't compatible. Surprise, it didn't work either, but the seller didn't want any return and just let me keep both for the price of one (or less?). 2) I grew confident that my hardware was USB-C only without DP capabilities. For reference, it's a TUXEDO Book BU1406 and has a USB but no DP indication near the port. – Peter Nerlich Jul 4 at 12:09
  • I will be playing around with Arch a lot more in the future, so I have little to no hesitation to play around with kernel patches for now, Though, as already said, I don't think the hardware supports it anyway. – Peter Nerlich Jul 4 at 12:14

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