Bug 504496

Just found https://bugs.kde.org/show_bug.cgi?id=464868

The "Flat" option is designed to remove all acceleration. There are two options here:
1. The option doesn't work
2. The option works but doesn't produce the result you're hoping for

If it's #1, you'll see literally no change when you uncheck "Pointer acceleration" on the mouse page and then click Apply. Let us know if that's what's happening.

If it's #2, then when you uncheck "Pointer acceleration" on the mouse page and then click Apply, the feel will change, but not in exactly the way you're hoping for. If this is what's happening, then it's a bug in the Libinput library itself.

Let us know, thanks!

In wayland, it's not possible to change to Flat, that is the problem. At least at this point.

Even if None Acceleration are selected in KDE, libinput remains in adaptive mode. That is part of the issue.

Mouse feel is noticeable less accurate / precise in wayland, possibly due to it, if not for more / other reasons. Compared to X11.

> Even if None Acceleration are selected in KDE, libinput remains in adaptive mode. That is part of the issue.
Ok, so you're able to use the setting, but it doesn't seem to work and change what you want.

Please report this to the Libinput folks at https://gitlab.freedesktop.org/libinput/libinput/-/issues/. THanks!

In KDE, it is possible to alter in X11 (set to flat), but not Wayland and from what I read, the issue are DE related.

Check the answer here https://discuss.kde.org/t/how-to-access-libinput-properties-in-wayland-for-an-external-touchpad/11730/2

Quote:
On Wayland, the compositor has exclusive access to the libinput API, so any configuration needs to be made through KWin.`

It is possible; you already said you're using the setting that sets it to Flat.

This is working for me, which means it's not broken in a general sense, but rather there's something else wrong here. Which is why I'm suspecting Libinput is not applying the Flat acceleration profile to your hardware as you expect.

I am using the setting that set to flat, in X11.

In wayland, when KDE setting Pointer Acceleration -> None, does not set libinput to flat, it stay in adaptive, that's the bug I said.

If I try set the profile in wayland with `libinput set-accel-profile`, results in `libinput: set-accel-profile is not installed`.

There are plenty of threads of this problems in KDE discuss alone, which has not been fixed.

---

You say it's working for you, does it mean you see the libinput flat mode active in wayland?

Yes, on Wayland, when I uncheck the "Enable pointer acceleration" option, there is an immediate and noticeable effect on the mouse pointer's tracking. So it's working for me.

Another potential option: could you have the wrong mouse selected in the device dropdown menu at the top of the page? That would also expect why disabling acceleration on Wayland isn't having the effect you expect.

Sure, there could be other factors involved in this.

But could you check with the command 

libinput list-devices

That should show your device and whether it's in flat, adaptive or another mode.

Well this is interesting. When I disable pointer acceleration in the Mouse KCM, the feel of the mouse *clearly* changes. However I can indeed see that libinput thinks it's in adaptive mode:

sudo libinput list-devices | grep -A 23 "Logitech USB Optical Mouse" | grep "Accel profiles"
Accel profiles:          flat *adaptive custom

So now I'm a bit confused about what's going on here! Re-opening.

Yeah. Thanks.

libinput is a library, not a system service. The command line utilities do not apply the settings of the compositor.

Why does it stay in that mode even with the supposely setting of disabled mouse accel in kde is done? 

It should be in flat mode.

https://discuss.kde.org/t/how-to-access-libinput-properties-in-wayland-for-an-external-touchpad/11730

Again, libinput command line tools do not know what settings the compositor is using. The text it prints is about what settings other libinput command line tools use for interpreting input events.