pseudo-switch is a program to emulate a tablet-mode switch for Linux devices with detachable keyboards.

pseudo-switch monitors for the keyboard being added or removed. When the keyboard is removed, it turns the tablet-mode switch ON, and when the keyboard is added, it turns the table-mode switch OFF.

pseudo-switch can be used, for example, with Sway's bindswitch tablet:on.

Building

cargo build --release

Usage

Identifying the Correct Device

First, identify the device for your detachable keyboard. Run:

pseudo-switch identify-detachable-devices

then try removing the detachable keyboard. The correct device should become grayed out.

It is recommended to use the path under /dev/input/by-path since it will not change regardless of the order in which devices are added.

Permissions

The user under which pseudo-switch is run must have write permissions for /dev/uinput.

Here's how you can check your permissions:

$ ls -l /dev/uinput
crw-rw----+ 1 root input 10, 223 Mar 12 22:37 /dev/uinput

$ groups
sys network power lp input

Running the Emulated Tablet-Mode Switch

pseudo-switch run /dev/input/by-path/<your-device>

For example, on my system, it would be:

pseudo-switch run /dev/input/by-path/pci-0000:00:14.0-usbv2-0:3.1:1.0-event-kbd  

You may wish to add hysteresis (a delay) to prevent rapid oscillation. For example, to add a 0.5 second delay:

pseudo-switch run --hysteresis 0.5 /dev/input/by-path/<your-device>

Adding a systemd Service

First install to /usr/bin/pseudo-switch. Then:

sudo pseudo-switch install-systemd-service --hysteresis 0.5 /dev/input/by-path/<your-device>

This will create, enable, and start a systemd service that will run at boot.

Using with Sway

The following in your sway config will rotate the display in tablet mode:

bindswitch tablet:on output eDP-1 transform 90
bindswitch tablet:off output eDP-1 transform 0