Ports on a Thunderbolt 3 dock are missing after unplugging/reconnecting, or suspend/resume

Sam Varshavchik

12/12/23, 1:49 PM

I'm having an annoying problem with a Thinkpad X1 running Ubuntu 20.04, and a Thunderbolt dock.

The dock works fine after the laptop boots. All ports, Ethernet and USB work fine.

All ports disappear after either:

Disconnecting or reconnecting the laptop from the dock.
Keeping the laptop connected to the dock, then suspending and resuming it.

The laptop still gets power from the dock, and responds to the on/off button from the dock, from this point on, so it's still communicating with it. But all the ports are gone. In all other respects the laptop functions normally.

After a random interval of time, anywhere between a few minutes to several hours, the ports come back by themselves, and work fine.

An immediate reboot also re-enables all ports as well.

I tried unplugging the laptop from the dock, resuming, then reattaching it to the dock. This made no difference. The laptop takes power from the dock, responds to the on/off button on the dock, but does not see any ports on it.

280

1 + 1

thinkpad

thunderbolt

20.04

Sam Varshavchik

3/10/24, 11:48 AM

No permanent solution. I only found that generating constant network traffic usually causes the ports to come up after a few minutes. I start Google Meet, with only myself in it, and let the camera stream my video into the void. Within seconds, or a few minutes, the ports come back up.

Score:0

Ubuntu

Ján Nosko

4/12/24, 6:46 AM

I am having the same problems with external monitor connected over USB-C to my Dell Latitude 5501. After hunting a solution for a months, I have finally found something working. By forcing linux to rescan PCI devices, the monitor comes back and xrandr finally sees it:

echo "1" | sudo tee /sys/bus/pci/rescan > /dev/null

More info: https://superuser.com/a/1046942

Optionally, you can install laptop-mode-tools, which are most probably using the same approach, but on my system it is sometimes causing the CPU to never go below maximum frequency: External monitor not detected by Ubuntu 19.04 after sleep

+ 2

David

4/12/24, 8:16 AM

The OP says the dock is the issue so not sure how this helps.

Ján Nosko

4/13/24, 10:17 AM

I believe the root cause is the same, that some of the PCI devices (in my case the monitor) is not visible by system. Forcing linux to rescan the PCI devices should fix the not working ports on the dock.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Ports on a Thunderbolt 3 dock are missing after unplugging/reconnecting, or suspend/resume

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.