I’ve actually figured out a temporary/local fix for this, but I’m posting here in the hopes that someone can upstream the fix, and/or in the hope that my solution will be helpful to someone else.
TLDR; add this to /etc/libinput/local-overrides.quirks:
[ELAN Touchpad]
MatchName=*ELAN*Touchpad*
AttrResolutionHint=31x31
AttrPressureRange=10:8
And then reboot.
Per the title I’ve got an ASUS Chromebook CX9 (DROBIT). I installed MrChromebox’s firmware without issue, and then installed Debian 12. The touchpad only sort of worked at first; I could drag the mouse around and single-click on things, but it felt laggy/poorly calibrated and multi-touch gestures like “2-finger click for right-click” or “2-finger drag to scroll” weren’t working.
I googled around and someone mentioned that they solved a similar problem by adding a libinput “quirk”. I looked through my system and found that both Asus and Elan (the touchpad manufacturer, I think) have quirks already defined, but they weren’t being applied because my touchpad device name didn’t match the patterns they were using. The fix above is a copy of one of the Elan quirk definitions, but with an updated MatchName to match my hardware.
When I run libinput list-devices I see (among other things) this device name:
Device: ELAN2701:00 04F3:31C6 Touchpad
Kernel: /dev/input/event8
Before applying the fix, running libinput quirks list /dev/input/event8 showed no quirks, afterwards it shows this as expected:
AttrPressureRange=10:8
AttrResolutionHint=31x31
I won’t pretend to understand what those lines mean, but I can confirm that “2-finger click to right-click” and “2-finger drag to scroll” now work for me. And moving the mouse feels a lot smoother now too.
I hope this is helpful to someone! If there’s any more info I can provide, please let me know!