Virtual keyboard for decrypting the disk

[LienRag]

I installed a Lenovo tablet (an x86 model) with a vanilla Debian, and one of the problems is that at boot, when prompted for the password that decrypts the disk, there is no virtual keyboard that spawns, which means that the tablet is not usable if one hasn't a USB keyboard nearby during boot.

It's quite logical that the minimum software loaded to decrypt LUKS doesn't have a virtual keyboard in it, but that made me think : how does Pinephone manage it ? I have an encrypted Pinephone, and (luckily for me) the virtual keyboard spawns when I boot, so that I can decrypt the partition which has the OS.

Not that I'd be able to port this solution to a Debian tablet, but still it made me curious...

[Kevin Kofler]

First of all, you need an unencrypted /boot partition so that the kernel can load and bring up a minimum userspace. If even /boot is encrypted, the passphrase prompt is done in GRUB, which does not support advanced features such as a virtual keyboard. And then the minimal userspace in the initramfs must contain the virtual keyboard, and the passphrase prompt must be done in an environment that supports it (usually an X11 or Wayland session).

[LienRag]

Indeed, I used the Debian installer automatic mode, so it may have encrypted /boot.
Thanks for the explanations.

the minimal userspace in the initramfs must contain the virtual keyboard, and the passphrase prompt must be done in an environment that supports it (usually an X11 or Wayland session)

 Would you per chance know whether something like that exist already for Debian (so I could just install it) ?

[fxc]

Indeed, I used the Debian installer automatic mode, so it may have encrypted /boot.
Thanks for the explanations.

the minimal userspace in the initramfs must contain the virtual keyboard, and the passphrase prompt must be done in an environment that supports it (usually an X11 or Wayland session)

 Would you per chance know whether something like that exist already for Debian (so I could just install it) ?

You can use osk-sdl (which is used in the PinePhone) in other distributions and installs too. It's for example in the Arch AUR.