Comment 6 for bug 1848108

@kaihengfeng
Following instructions here,
https://wiki.ubuntu.com/Kernel/MainlineBuilds
I've installed generics, rebooted, and was welcomed to the blinding white void.
Hazarding a guess, I typed in my system's encryption password and it subtly changed brightness like it usually did and a mouse cursor appeared. So that's something.
Switching to a virtual console still was white but I was able to blindly login and type in `sudo reboot now` and switch back to a stable kernel.

Removing a workaround employed here,
https://forums.lenovo.com/t5/Other-Linux-Discussions/ThinkPad-E485-E585-Firmware-bug-ACPI-IVRS-table/td-p/4191484
particularly the `ivrs_ioapic[32]=00:14.0` line didn't resolve and just left me hung after GRUB like it did normally.