🐧 Fixing thunderbolt 3 hotplugging on Lenovo Yoga C940 (and other Lenovo Yoga/Ideapad devices) (and possibly other devices with MIMO BAR)

Posting this here because the information still seems to be impossible to find without days of useless googling/ddg'ing. This should hopefully at least be somewhat easier to find through a search engine.

If you run linux on your Lenovo laptop, there is a good chance your thunderbolt actually isn't working. I was fine with it until I bought myself a thunderbolt dock. You may be fine with it as well if you never want to hotplug tb3 devices, but if you do, and you find they don't work, try patch 287661 from here https://bugzilla.kernel.org/show_bug.cgi?id=206459

You'll have to scroll a bit to find it. You could also just search for 287661. Keep in mind that there is no reason to do this unless you need hotplugging support for thunderbolt 3.

Really hope this saves someone a few hours of headache. You'll still have to compile a kernel for yourself with the patch applied, but at least that is documented decently, unless you are on fedora of course, in which case I might direct you to the original guide https://fedoraproject.org/wiki/Building_a_custom_kernel (which as of 2021.Apr.27 is still not working), and the forum post I dug up which fixed my custom kernel problems https://forum.level1techs.com/t/compile-fedora-kernel-the-fedora-way/149242 . Or you could possibly read the guide I wrote over on https://odysee.com/@mumblingdrunkard:7/20210405-fedora-patch-compile-and-install-kernel:0 which essentially summarizes most of it step by step.

If anyone has the time and or authority to push this issue further up so I can go back to not compiling my own kernel, that would be greatly appreciated.

Your pal,

mumblingdrunkard