Comment # 3 on bug 1188352 from Guillaume GARDET

(In reply to Jonas del Campo from comment #2)
> Tested also with latest kernel 5.13.4-1-default, same result.
> 
> However I've noticed that I can type the LUKS password with an external USB
> keyboard. Could that mean that the internal keyboard relies on some
> module/driver? I couldn't find anything obvious with lsmod.

It looks like this, indeed. 
On-board keyboard seems to be on USB2, but you likely connected the external
keyboard on USB3 port, right?

I think there is a power supply or a gpio missing. Could you share the output
of 'lsmod', please?