Fan runs full speed forever after waking from suspend

I have a Lenovo ThinkPad X1 Carbon (5th gen., type 20HR) that works wonderfully with Ubuntu 16.04 but for one thing: the fan often (but not always) comes on full after waking the laptop from suspend, and then stays in indefinitely.

Before suspending, it is quiet and does sometimes spin up for a few seconds now and then (so it seems that some sort of temperature control is working). When it stays on, it doesn't feel like it's hot at all, and the CPUs are often under 10% each.)

How can I make the fan behave itself?

Solution 1:

I have the same problem, and after doing some research, looks like this was a kernel regression triggered by latest X1C firmware. There is a long discussion here: https://bugzilla.kernel.org/show_bug.cgi?id=191181 And a bug report here for the X1C 5th Gen specifically: https://bugzilla.kernel.org/show_bug.cgi?id=196129

Some people are reporting those patches are working for them. But it doesn't seem a foolproof fix has made it into mainline kernel yet.

EDIT: I have been running kernel 4.12.10 for a few days now and this issue has not resurfaced. I followed these instructions to install it: https://www.tecmint.com/upgrade-kernel-in-ubuntu/. Hope this works for you as well!