For a bit of reference for anyone interested, some output from `xinput`:
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Logitech M510 id=8 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Power Button id=7 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=9 [slave keyboard (3)]
↳ HP WMI hotkeys id=10 [slave keyboard (3)]
Device 'Logitech M510':
Device Enabled (132): 1
Coordinate Transformation Matrix (134): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Accel Speed (267): 1.000000
libinput Accel Speed Default (268): 0.000000
libinput Accel Profiles Available (269): 1, 1
libinput Accel Profile Enabled (270): 1, 0
libinput Accel Profile Enabled Default (271): 1, 0
libinput Natural Scrolling Enabled (272): 0
libinput Natural Scrolling Enabled Default (273): 0
libinput Send Events Modes Available (252): 1, 0
libinput Send Events Mode Enabled (253): 0, 0
libinput Send Events Mode Enabled Default (254): 0, 0
libinput Left Handed Enabled (274): 0
libinput Left Handed Enabled Default (275): 0
libinput Scroll Methods Available (276): 0, 0, 1
libinput Scroll Method Enabled (277): 0, 0, 0
libinput Scroll Method Enabled Default (278): 0, 0, 0
libinput Button Scrolling Button (279): 2
libinput Button Scrolling Button Default (280): 2
libinput Middle Emulation Enabled (281): 0
libinput Middle Emulation Enabled Default (282): 0
Device Node (255): "/dev/input/event12"
Device Product ID (256): 1133, 16465
libinput Drag Lock Buttons (283): <no items>
libinput Horizontal Scroll Enabled (284):
I don't quite have any PS/2 mice to test anymore, however I have tested the following devices, and confirmed they all posess the 'libinput Accel Speed' property, and exhibit acceleration changes when requested:
An interesting note, perhaps, is that neither user I tested with, is in the 'input` group.
Also, I don't have '/etc/X11/xorg.conf.d/10-libinput.conf' config file. So I just created it, and added the following option line:
Option "AccelSpeed" "float"
Where "float" is a doubled quoted value ranging from "1" to "-1". So my '/etc/X11/xorg.conf.d/10-libinput.conf' currently looks like this:
Section "InputClass"
Identifier "CorePointer"
MatchIsPointer "yes"
Driver "libinput"
Option "AccelerationScheme" "predictable"
Option "VelocityScale" "20"
Option "AccelerationProfile" "5"
Option "AccelerationNumerator" "15"
Option "AccelerationDenominator" "1"
Option "AccelerationThreshold" "1"
Option "AccelSpeed" "1"
EndSection
So, a few questions for clarity, if I may, Mesh Malachi. You have been using the correct ID number for your device? Your device also apparently supports the 'Accel Speed' property? And, what if you edit your '/etc/X11/xorg.conf.d/10-libinput.conf' and add the 'AccelSpeed' option?