No Thunderbolt Display Output on T470

[Tedward]

I assumed since it's a Thunderbolt 3 port that it would support Display
Port out, but I'm unable to get any video signal.

I am running Arch Linux. Under xrandr I see the following screens: eDP1,
DP1, DP2, HDMI1, HDMI2 and VIRTUAL1. I am using HDMI2 without any issues
to drive my external monitor but it's limited to 4k@30hz only while the
DP over Thunderbolt should be capable of 4k@60hz. Trouble is, I haven't
been able to find a way to get a signal out of that port. Even xrandr
shows it as disconnected while plugged in. Similarly, plugging in a
USB-C device to charge over the port does not register anything on
either the charging device or the laptop via dmesg. So, I'm at a loss.
Is this port busted or is there a setting somewhere I've missed to
enable it?

// T

[psvrh]

I understand you're using Arch, but had you tried seeing if it works
under Microsoft Windows? Or do you have a USB-C thumbdrive that might
show as bootable in BIOS?

Either way, the TB port on these laptops is a ticking time bomb and
there's been a lot of chatter about why and if/how it could be fixed.

Have a look at:
*
https://www.reddit.com/r/thinkpad/comments/eszg2o/thinkpad_tb3_failure_what_we_know_repair/

*
https://www.notebookcheck.net/ThinkPad-Thunderbolt-3-failure-What-s-happening-why-it-s-happening-and-how-to-fix-it.451207.0.html

tl;dr, the non-volatile memory backing the TB controller burns out.
You might be able to fix it and/or solder a new chip and/or replace the
motherboard. Be careful replacing the motherboard if you go that route,
as a **lot** of these machines suffered this failure, and a lot of
replacement motherboards have dead TB ports.