Linux

I’m going to preface this and say that I don’t use Debian or Sway but I think I can help explain the reddit post a bit. On mobile, please excuse the formatting.

Wayland is a protocol that isn’t responsible for drawing anything to your screen by itself. This job is done by a Wayland compositor. (They’re similar to window managers on an X11 system if that means anything to you)

Sway is one such compositor that Debian supports, but it also supports GNOME and KDE Plasma which have their own compositors and the wiki mentions Weston as well.

It looks like Debian defaults to GNOME, so the sway commands aren’t going to be much help. Wayland uses libinput to handle peripherals so none of the xinput commands are going to be usable.

It’s a little in depth and probably not the best way to do things, but I think I have a solution that might work. Hopefully this can at least get you started, let me know if you have any questions!

Reddit implies that in settings -> keyboard -> shortcuts you can create a shortcut to execute arbitrary commands. You should be able to bind a key to “gsettings set org.gnome.desktop.peripherals.mouse speed 0.0” which will keep your cursor from moving and another with the “0.0” at the end changed to something like “0.5” to set the cursor speed back to something reasonable. This could be done as a shell script to toggle back and forth with one key.

My first thought (which probably isn't the best method, but I've done similar before) is an Arduino between the mouse and the system. The Arduino normally just passes the mouse commands to the system, but it listens for the button and blocks movement if it sees the button press.

Because it's all done in hardware, this method would be system-agnostic. You could plug it into anything.

I used a Teensy 3.6 for a similar project.

~~There is a accessibility setting to disable touchpad when typing. You could try to hack into it to disable your mouse.~~

From quick look at it I don't think it possible

Success! This is certainly a niche issue, but since it's taken a pretty lengthy amount of research to resolve, I thought I'd add some resources here in case it's helpful to anyone else.

After exploring others' recommendations, I've saved hardware solutions for tinkering in the future and was also not able to find a way to temporarily disable mouse movement through gnome. I finally landed on python-evdev as my solution. With this, you can read input from one or more devices simultaneously, create a virtual input device to write events to on-demand, and (maybe most importantly) retain exclusive access to the original hardware devices to absorb their input. I'll also shout out evsieve which lead me to python-evdev. The python-evdev documentation is quite thorough, and it's quite a custom solution based on your own needs, so I'm not going to go into great detail on my python script - but it's only 27 lines long, nothing major.

Be aware that you may need to write some udev rules to allow access to the physical devices and to allow the virtual device to be created. This was the easiest part for me to find help with, so I'll leave some abridged copy/paste details below:

Find your device Vendor and Product IDs cat /proc/bus/input/devices | more

Write a udev rule (I used priority 71) to allow access to the device: SUBSYSTEMS=="usb", ATTRS{idVendor}=="", ATTRS{idProduct}=="", TAG+="uaccess"

Add a very poor udev rule to allow a virtual device to be created by python-evdev (there's probably a much better way to do this): KERNEL=="uinput", SUBSYSTEM=="misc", OPTIONS+="static_node=uinput", TAG+="uaccess", MODE="0660"