GRUB2 freezes after loading at_keyboard

[Klaus Bielke]

Try these commands on GRUB command line:

insmod at_keyboard
terminal_input at_keyboard console
terminal_input console

Now GRUB doesn't accept any keypress.

Or chainload to another GRUB with at_keyboard active on terminal_input. New GRUB cannot controlled by keyboard, but starts default menuentry after timeout.

Module at_keyboard is important for localisation, e.g. using a german keyboard layout.

[Julian Andres Klode (juliank)]

Low priority because

- this module is not built-in, and hence cannot be used on secure boot systems, so it's only usable on legacy and custom systems in the first place
- it is an usual end user configuration, given that there is not even a configuration option for it
- it's not necessary for booting the system, unless you have /boot inside LUKS and layout differences matter for the password, but that's again an unusual system configuration
- there is an easy workaround of just typing with ANSI layout in mind

[Mate Kukri (mkukri)]

the at_keyboard module of GRUB takes control of the keyboard controller from firmware while the firmware is still running, it should come with a 'There be dragons' disclaimer.

additionally at_keybaord doesn't work if you are using a USB keyboard and the firmware doesnt provide SMM based PS/2 emulation which is about 100% likely on mondern UEFI

[Mate Kukri (mkukri)]

And additionally we don't support encrypted /boot, and password entry on initrd unlocked FDE does not happen in GRUB