maccel

Linear mouse acceleration.

Acceleration Function

$$V = \frac{\sqrt{dx_0^2 + dy_0^2}}{i}$$

$$dx_f = dx_0 * (1 + aV)$$

$$dy_f = dy_0 * (1 + aV)$$

Where $dx$ and $dy$ are the directional displacements read from the mouse, $i$ is the polling interval of the mouse; this would be 1ms if the polling rate is 1000Hz, and $a$ is the user provided acceleration factor

Install

Make sure to have these dependencies installed on your machine: curl, git, make, gcc, and the linux headers in /lib/modules/

curl -fsSL https://www.maccel.org/install.sh | sudo sh

Uninstall

sh /opt/maccel/uninstall.sh

Or

curl -fsSL https://www.maccel.org/uninstall.sh | sudo sh

CLI Usage

CLI to control the parameters for the maccel driver, and manage mice bindings

Usage: maccel <COMMAND>

Commands:
  tui        Open the Terminal UI to manage the parameters and see a graph of the sensitivity
  bind       Attach a device to the maccel driver
  bindall    Attach all detected mice to the maccel driver
  unbind     Detach a device from the maccel driver, reattach to the generic usbhid driver
  unbindall  Detach all detected mice from the maccel driver reattach them to the generic usbhid driver
  set        Set the value for a parameter of the maccel driver
  get        Get the value for a parameter of the maccel driver
  help       Print this message or the help of the given subcommand(s)

Options:
  -h, --help     Print help
  -V, --version  Print version

Notes

One should disable the acceleration done by default in some distros, e.g. by xset or libinput. Full Guide

Here is Breakdown of why and how I ended up making this

Troubleshooting Install

gcc

The version matters, it must match the version with which the kernel was built.

For example you might encounter such an error:

And you'll have to find a version of gcc that matches. This will be more or less annoying depending on your distro and/or how familiar you are with it.

linux headers

You want to make sure that /lib/modules/ is not empty. For example mine looks like this:

total 0
drwxr-xr-x 1 root root    114 Jan 29 17:59 .
drwxr-xr-x 1 root root 159552 Jan 29 22:39 ..
drwxr-xr-x 1 root root     10 Jan 29 17:59 6.6.14-1-lts
drwxr-xr-x 1 root root     12 Jan 29 17:59 6.7.0-zen3-1-zen
drwxr-xr-x 1 root root    494 Jan 29 17:59 6.7.2-arch1-1
drwxr-xr-x 1 root root    494 Jan 31 21:54 6.7.2-zen1-1-zen

You want to find headers that match your kernel as represented by

uname -r

On an arch based distro you search for the available headers with

sudo pacman -Ss linux headers

Troubleshooting Driver

If you notice any weird behavior and are looking to investigate it, then try a debug build of the driver. Run this modified install command.

curl -fsSL https://www.maccel.org/install.sh | sudo MACCEL_DEBUG_INSTALL=1 sh

This debugging experience might be lacking still. Feel free to report any issues.

References

• https://lwn.net/Kernel/LDD3/
• https://github.com/torvalds/linux/blob/master/drivers/hid/usbhid/usbmouse.c
• https://www.kernel.org/doc/html/latest/input/index.html
• https://github.com/a1xd/rawaccel/blob/master/doc/Guide.md
• https://github.com/Skyl3r/leetmouse/blob/master/driver/accel.c
• https://sourceforge.net/p/fixedptc/code/ci/default/tree/
• https://github.com/torvalds/linux/blob/master/drivers/input/evdev.c
• https://github.com/freedesktop-unofficial-mirror/evtest/blob/master/evtest.c
• https://docs.kernel.org/input/input-programming.html
• https://www.kernel.org/doc/Documentation/input/input.txt
• https://docs.kernel.org/driver-api/input.html
• https://linux-kernel-labs.github.io/refs/heads/master/labs/device_drivers.html
• https://www.youtube.com/watch?v=oX9ZwMQL2f4
• https://gist.github.com/fstiehle/17fca11d7d1b4c2b8dfd982e1cf39caf