Installed tumbleweed from recent installation media onto a desktop machine.
Rebooted, and all works fine.
Sometime later, do a zypper dup, from virtual console at multi-user target, which succeeds with no errors.
At next reboot, keyboard works at grub, but at any point afterward, it nor (integrated in keyboard) touchpad, nor other spare keyboard, produce any response on screen.
The only exception might have been at partition decryption password entry prompt, although rescue mode / single user somehow has the problem anyway.
Tried but did not help…
All the other usb ports
Boot from prior kernel
Boot live, and removed any of the new packages (ignored the updated packages) added by the zypper dup
Boot live, mount the root partition, setup a proper jail, chroot into it, zypper dup the system again
Checked logs for related errors
Each of the potential i8042 kernel params like i8042.dumbkbd=1
Various other kernel params as advised in forums
Reinstall tumbleweed fresh
These various uefi configs as advised in forums are not present in uefi options so could not try them…
Enable XHCI Handoff
Disable EHCI Handoff
Ultimately, if there’s something someone can suggest that’s not too difficult to try, then let’s give it a shot. Otherwise, it’s probably not worth going down a troubleshooting rabbit hole, considering everything that’s been tried so far.