Linux/Ubuntu on FW16 - Thunderbolt is extremely intermittent

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Generally happy with my new Framework 16 with Ryzen 7840HS, but I’ve got this frustrating problem – Thunderbolt only seems to work on some of my ports, and which of those ports changes depending on… I dunno… the position of Mercury or something.

I have a Lenovo TB4 dock (40B0) with a keyboard, mouse, and two monitors. I’m on Ubuntu 25.04 (which I know isn’t an ‘officially’ supported Ubuntu version but oh well). I know that all six ports are working for USB2-type features, because I can plug my keyboard into any spot and it works. USB-PD charging on ports 1, 2, 4, and 5 also works, either through a charging cable or the dock.

But when I plug in my dock, the laptop only sees it as a dock some of the time. Typically it’s ports 2 and 5 that work most consistently, and typically it only changes on reboot (and only sometimes) but port 5 also just stopped working after an unplug and replug.

I’ve tried a different OS (the same live USB that I used to install Ubuntu on my laptop, as well as a Fedora live USB) and the results are similar.

The only interesting line when I plug the dock into a non-functioning port is:

2025-10-22T13:09:45.999783-07:00 panda-paul kernel: ucsi_acpi USBC000:00: UCSI_GET_PDOS failed (-70)

And that’s the only message I see on plugin. When I plug it into a functioning port, I get a bunch of the usual expected messages PLUS that line.

Trying to plug my monitor in directly, I get signal on ports 1, 2, and 4, but on port 5 my monitor tells me the laptop doesn’t support DP Alt mode. If I come back another time, it’ll be a different set of ports, I’m sure.

Has anyone experienced something like this? It’s puzzling, and the syslog gives me no great hints about what might be wrong. Currently typing this on my laptop keyboard because somewhere in the plumbing, the laptop or the dock has lost the ability to recognise the USB keyboard, mouse, and trackpad.

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This does not really answer your question, but here’s a link to a map of the possible functions of the different ports:

The “port 5 tells me the laptop doesn’t support DP Alt mode” thing is to be expected.

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When the dock isn’t working try running lspci. This seems odd that it might help but it forces some of the devices out of runtime power management.

So it’s possible it gets it enumerating and helping.

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oh, will you look at that, you’re right. What’s puzzling is I’m pretty sure I’ve been successful using both the dock with DP Alt mode and the HDMI expansion card in port 5, but now I’m not sure. Anyhow, I guess that narrows down my troubleshooting options a bit.

I’ll give that a try next time I’m plugged in; thanks for the “one weird trick” :slight_smile:

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Wow, lspci did the trick for me.

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THIS IS SORCERY!

Too soon to tell, because I’m not sure if it was actually having problems on this reboot, but… I think it worked for me too! Thank you!

(now if only it would wake from sleep more than 20% of the time… this reminds me of my Windows 98 days)

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