Monitor is not detected

[johnsongw]

Originally Posted by Gaboto

I use Ubuntu 20.04

I had encountered similar, or maybe I should say identical issue, on a freshly install Ubuntu 20.04 on Lenovo X13. I am not sure if it's hardware related.

One thing I noticed in common is our laptop detected the new monitor as:

: new high-speed USB device number 10 using xhci_hcd
: New USB device found, idVendor=0bda, idProduct=5412, bcdDevice= 1.27
: New USB device strings: Mfr=1, Product=2, SerialNumber=0
: Product: 2-Port USB 2.1 Hub
: Manufacturer: Generic
: USB hub found
: 2 ports detected
: new full-speed USB device number 11 using xhci_hcd
: not running at top speed; connect to a high speed hub
: New USB device found, idVendor=0bda, idProduct=5450, bcdDevice= 0.06
: New USB device strings: Mfr=17, Product=18, SerialNumber=19
: Product: BillBoard Device
: Manufacturer: Realtek

This is puzzling. Based on the documentation it seems that the monitor's USB vendor ID should be 17e9

https://support.displaylink.com/knowledgebase/articles/683672-my-displaylink-device-does-not-work-on-ubuntu

I have tried the github manner, as well as installing the vanilla displaylink-driver-5.4.1-55.174.run. same observation.

Would greatly appreciate any advice / idea / pointer. Thank you.

PS: forgot to mention, the vanilla displaylink driver and the same Asus monitor works on a Dell laptop, fresh Ubuntu 20.04 installation. lsusb shows correct vendor ID on that Dell laptop

[sdjf]

I am dealing with monitor issues as well, with a quite different scenario, on a totally different system, but it seems to me that the kernel is not seeing the monitor's DisplayLink chip, or it would show in lsusb.

My experience is with a DoubleSight monitor on ArchLInuxArm, which is quite different than your systems, but still, I would expect the monitor to show up, even if it is not attached to the correct driver.

Instead, it is shown as a hub? Possibly it is not getting enough power? Is it plugged in to a hub? Have you seen lsusb output, and especially lsusb -t output, for someone who has gotten this monitor to work on Ubuntu? I bet that in the device tree, DisplayLink will show up.

Also, try lsusb -t on your system without the DisplayLink plugged in - If lsusb -t looks the same, then it is not getting seen by the kernel.

Another possibility is that the device and product ID are not interpreted properly, it should be seen as an I/O device even if it is not claimed by any driver, I believe.

EDIT: Did a bit of googling, did not come up with an answer but it seems important to look at information about "Billboard Devices". There may be power issues, because of how various USB standards work. Also look at Power Delivery issues (abbreviated PD). It may require some sort of docking station to resolve them.