osk-touch

This is a framebuffer onscreen keyboard for TTY, specifically intended for Steam Deck. It might be useful for accessibility. You can touch the screen to send the keystrokes to the system, like a real keyboard.

• No extra libraries. Great for using at boot time:

# ldd osk_touch
	linux-vdso.so.1 (0x00007ffc49159000)
	libc.so.6 => /usr/lib/libc.so.6 (0x00007fa930b43000)
	/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007fa930d39000)

• Onscreen keyboard using framebuffer
• It reads touchscreen and sends keystrokes using uinput

The deck_keyboard.ppm is the keyboard image. It is a screenshot of Valve's keyboard edited with GIMP and exported as raw ppm.

How to use

• If you are using SteamOS, you need my SteamOS on-device native unsandboxed toolchain guide or any equivalent C toolchain you prefer that you can get to work with this app.
• Be sure that "FTS3528:00 2808:1015" is the name of your touchscreen. That is the name of the Steam Deck's touchscreen and is used by default.
• Check which is your framebuffer device (/dev/fb0, /dev/graphics/fb0, etc). /dev/fb0, that of SteamOS, is used by default.
• You need root for commands marked with #.
• If you experience crashing after updating your OS, you need to update your toolchain too and recompile this app.

$ make
# chvt 4
# modprobe uinput
# ./osk_touch &

How to disable automatic login, drop to tty4 on boot, and launch osk-touch

Example focuses on SteamOS. Directions must be adapted where necessary for other distros.

• After compilation, install osk-touch to the writable, persistent /home/ folder:

# cp osk_touch /home/
# cp deck_keyboard.ppm /home/

• Create a script in /home/ named osk-touch.sh with this content:

#!/bin/bash
chvt 4
/home/osk_touch

• Mark the script executable:

# chmod +x /home/osk-touch.sh

• Create a service in /etc/systemd/system/ named osk-touch.service:

[Unit]
Description=Touchscreen keyboard for Steam Deck TTY

[Service]
Type=simple
Restart=always
RestartSec=5
WorkingDirectory=/home
ExecStart=/home/osk-touch.sh

[Install]
WantedBy=multi-user.target

• Disable automatic starting of SDDM, which will disable automatic login, and enable osk-touch.service:

# systemctl disable sddm
# systemctl enable osk-touch