osk-sdl_arch

Getting osk-sdl working to help decrypt tablets and other touchscreen enabled devices running x86_64 bit Arch Linux.

Forked PKGBUILD and related files originally from https://github.com/dreemurrs-embedded/Pine64-Arch

osk-sdl main project, code, and bug reports can be found at https://gitlab.com/postmarketOS/osk-sdl

Issues regarding how this package works can be filed here.

Issues regarding how osk-sdl works in general should be brought up with the official repository at: https://gitlab.com/postmarketOS/osk-sdl/-/issues

Installation

sudo pacman -S --needed base-devel git
git clone https://aur.archlinux.org/osk-sdl.git
cd osk-sdl
makepkg -fsri

Configuration

Make sure osk-sdl is installed to your system and then add osk-sdl to your /etc/mkinitcpio.conf hooks. osk-sdl should be inserted before the filesystems hook but after udev or systemd hook. Optionally include the keyboard and keymap hooks if your device has a detachable keyboard or if you sometimes want to plug in a USB or OTG keyboard for passphrase input.

Example:

 HOOKS=(base udev autodetect keyboard keymap consolefont modconf block lvm2 osk-sdl filesystems fsck)

Next you will want to make sure you incude the necessary kernel modules to support the display and touchscreen. Add those to your /etc/mkinitcpio.conf modules.

Example list of modules taken from a HP Pro Tablet 408 G1. i915 for the Intel graphics hid_multitouch,i2c_hid, i2c_hid_acpi for touchscreen support THESE WILL BE DIFFERENT DEPENDING ON YOUR DEVICE

MODULES=(i915 hid_multitouch i2c_hid i2c_hid_acpi)

Generate a new init with mkinitcpio -P

Lastly make sure you've added the proper device to your kernel command line. mkinitcpio generation includes variables from the kernel command line.

 cryptdevice=device:dmname

* device is the path to the device backing the encrypted device. Usage of persistent block device naming is strongly recommended.

* dmname is the device-mapper name given to the device after decryption, which will be available as "/dev/mapper/dmname"

* If a LVM contains the encrypted root, the LVM gets activated first and the volume group containing the logical volume of the encrypted root serves as device. It is then followed by the respective volume group to be mapped to root. The parameter follows the form of "cryptdevice=/dev/vgname/lvname:dmname".

Optionally add osk_kms= to your kernel command line with a comma separated list of modules you need for osk-sdl to work but cause issues when being loaded too early in boot, this will trigger those modules to be unloaded immediately after unlocking so they can be loaded later. This is to workaround issues such as the KMS backlight issue where backlight controls completely stop working keeping the device at full brightness. This is caused when some video drivers are loaded too early in boot taking control away from userland.