Here’s another story from my “WTF, computer?!” files (and also my “oh I’m dumb” files).
As I regularly do, I recently updated my Fedora machines. This includes the crappy HP 2000-2b30DX Notebook PC that I bought as a refurb in 2013. After dnf finished, I rebooted the laptop and put it away. Then while I was at a conference last week, my wife sent me a text telling me that she couldn’t type on it.
When I got home I took a look. Sure enough, they keyboard didn’t key. But it was weirder than that. I could type in the decryption password for the hard drive at the beginning of the boot process. And when I attached a wireless keyboard, I could type. Knowing the hardware worked, I dropped to runlevel 3. The built-in keyboard worked then.
I tried applying the latest updates, but that didn’t help. Some internet searching lead me to Freedesktop.org bug 103561. Running dnf downgrade libinput and rebooting gave me a working keyboard again. The bug is closed as NOTABUG, since the maintainers say it’s an issue in the kernel, which is fixed in the 4.13 kernel release. So I checked to see if Fedora 27, which was released last week, includes the 4.13 kernel. It does, and so does Fedora 26.
That’s when I realized I still had the kernel package excluded from dnf updates on that machine because of a previous issue where a kernel update caused the boot process to hang while/after loading the initrd. I removed the exclusion, updated the kernel, and re-updated libinput. After a reboot, the keyboard still worked. But if you’re using a kernel version from 4.9 to 4.12, libinput 1.9, and an HP device, your keyboard may not work. Update to kernel 4.13 or downgrade libinput (or replace your hardware. I would not recommend the HP 2000 Notebook. It is not good.)