Touchpad with flat profile cannot be set fast enough
Summary
I have Ubuntu 21.10 running an Xorg session on a laptop with an Elantech touchpad. I would like to have a "flat" acceleration profile with enough speed, but the range of allowable values for "Accel Speed" does not allow this.
Steps to reproduce
First of all, enable the "flat" profile for the touchpad with xinput (this is not exposed via any Ubuntu/Gnome UI):
xinput set-prop 'ETPS/2 Elantech Touchpad' 'libinput Accel Profile Enabled' 0, 1
I don't really understand what 0, 1 means, but I assume it is something like normalprofile=0 flatprofile=1. The default was 1, 0
. But it works, and the touchpad behaves as I expect -- with the cursor distance proportional to finger distance.
Then set the speed to maximum:
xinput set-prop 'ETPS/2 Elantech Touchpad' 'libinput Accel Speed' 1.0
For this value, a finger swipe across 100% of the touchpad makes the cursor move about 60% of the way across the screen. This is what seems far too slow for me.
Incidentally, if I try to set this to eg 1.1, I get an error. If I set it to -1.0, the cursor moves only a few pixels in total for a finger swipe across 100% of the touchpad.
Notes
I realize that preferred touchpad settings are subjective. However I feel that my own preferences here are fairly normal, and either that there's something wrong with my hardware/configuration that is making this very slow, or that if it's intentional then this speed would be too slow for a significant proportion of users.
I believe the ability to use a flat profile for touchpads was added after this issue: #283 (closed).
(I have virtually no understanding of how xinput/libinput/Wayland/X all work together or not in case this report is nonsensical.)
Required information
- libinput version: 1.18.1
- hardware information: Lenovo Ideapad 510S-14ISK