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ccook13

Member

Registered: 2020-09-29

Posts: 7

USB-C Hub w/ HDMI & DP stopped working after update

I have a Thinkpad T14 AMD Gen 1, and I've used both an Anker & CableMatters USB-C hub alternately to get an extra HDMI out for my work setup. Both hubs stopped working to provide an extra display-out earlier this week, and looking back through my pacman.log for anything related to display drivers, I saw that mesa, libva, and some other similar packages got minor bumps. Does anyone know if these packages could be the culprit, or if not, what packages could be? I have a list with package names and version changes from the past week if anyone needs it.

Under xrandr, I get my main laptop screen, eDP, the onboard HDMI out, HDMI-A-0, then two DisplayPorts, 0 & 1, that are shown as disconnected regardless of the hubs being connected or not.

[Edit 1]

Under lsusb, the hubs still show up, the controller/main chip(?) is from a "VIA Labs, Inc." for both of them.

Last edited by ccook13 (2023-09-01 17:13:58)

Lone_Wolf

Member

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 11,367

Re: USB-C Hub w/ HDMI & DP stopped working after update

Do those hubs use USB-C alternate DP or Thunderbolt mode ? see https://en.wikipedia.org/wiki/USB-C#Alt … ifications

If so a change on kernel level is the most likely cause.
Was your kernel in the list of updated pacakges ?

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Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

(A works at time B)  && (time C > time B ) ≠  (A works at time C)

ccook13

Member

Registered: 2020-09-29

Posts: 7

Re: USB-C Hub w/ HDMI & DP stopped working after update

Do those hubs use USB-C alternate DP or Thunderbolt mode ? see https://en.wikipedia.org/wiki/USB-C#Alt … ifications

If so a change on kernel level is the most likely cause.
Was your kernel in the list of updated pacakges ?

Per the product page for the main one (Cable Matters), it operates in DP Alt Mode, and did so for the longest time.

I run the Zen kernel, and it did get updated on Saturday the 26th, from 6.4.11.zen2 to 6.4.12.zen1; I would have first noticed the hub not showing a display the following Monday (the 28th) when I got back to my workspace. Not sure what could have been in that but it seems maybe something changed. I'll do some digging, thanks Lone_Wolf. If anyone has any knowledge if DP Alt Mode changed in that particular kernel or related kernels, any information is welcome.

ccook13

Member

Registered: 2020-09-29

Posts: 7

Re: USB-C Hub w/ HDMI & DP stopped working after update

It seems per this article and the linked patch series on kernel.org shows that an upgrade to allow support for DisplayPort 2.1 Alt Mode was in the works in the time leading up to my kernel update. Haven't gone thru it yet but maybe this is the ticket. I'll try downgrading to a previous kernel when I get home tomorrow.