The debounce, wheel/wheel-low-res, double-tool and eraser-button plugins can limit
themselves to a specific usage.
The mtdev plugin needs to pass each each event to mtdev and the proximity
timer plugin needs to get each event's timestamp so they cannot be
restricted.
The forced-tool could be restricted but effectively any event on the
devices it works on will have one of those usages set so there's no
point.
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1271>
For mice with multipliers 30/120 and 40/120 nothing would change
as both will still cross threshold only after 2nd event.
But for MX Master 3 (and maybe others) that makes scroll beginning
a bit responsive, without jumping straight to 64/120 or 72/120.
Now events being emitted at 16+16+16 or 24+24 without significant
side-effects ("twitching" when resting finger on the wheel,
sudden scroll events when pressing middle button, etc). See !1262 for
some background.
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1267>
The MX Master 3 is difficult, its wheel events are all over the place
and heuristics are tricky to determine. The previous plugin behavior
was seemingly sufficient for the MX Master but not for other devices.
Restore the old behavior if the quirk is set for a device by adding a
fourth state ALWAYS_ACCUMULATE. In this state the min movement is never
updated from the original threshold, causing any wheel motion to
accumulate.
Ref: ca6b82841c ("plugin/wheel: tighten the wheel debouncing code")
Ref: bb05e0d1b5 ("plugin/wheel: don't accumulate for low HID resolution multipliers")
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1262>
Accumulating (and partially discarding) scroll wheel events serves to
debounce a scroll wheel and provide for more fluid scrolling where
scroll wheels can send events going in the wrong direction.
This is unlikely to happen on devices with low resolution multipliers
(i.e. where some significant physical movement by the wheel is required
to trigger events) so let's make it contingent on devices more likely to
have flaky wheels.
The magic threshold picked is 30 (HID resolution multiplier of 4) as a
guess. The resolution multiplier isn't accessible in userspace so we
have to heuristically get to it - typical interaction with a mouse will
have that value set within the first two, three scroll wheel events
though.
Closes#1150
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1261>
The previous approach had a fixed threshold of 60 (half a detent)
below which scroll events were ignored. Reduce this threshold to have a
threshold of one device-specific delta. That threshold adjusts over time
to the device's individual minimum delta so after a few scroll event it
should settle on the lowest value possible.
The result is that fine-grained scrolling is possible on those devices
and only the very first scroll event is held back/swallowed, two events
in the same direction release scrolling.
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1258>
Touchpad devices are pointers too in libinput but they don't usually
have wheels. Let's check for REL_WHEEL in device_new *and* then again
for the actual pointer capability in device_added.
Fixes: d1800a76fe ("evdev: Handle scroll wheel with a plugin")
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1251>
