Revert the clickpad detection mechanism to it's previous state
Filing this mostly so it doesn't get lost: In a37d6dcc we changed the detection so any device with a right button is assumed not to be a clickpad, see #595 (closed). This was in response to several touchpads that needed quirks, based on the assumption that
To my knowledge, devices right now erroneously advertise INPUT_PROP_BUTTONPAD when they are not a clickpad (but then they have BTN_RIGHT) or they lack INPUT_PROP_BUTTONPAD (and only have BTN_LEFT).
This assumption is incorrect, as the set of commits since shows: 89cd0f99, #674 (closed), 1773973d and possibly others.
Worse, the detection now breaks the touchpads - previously a clickpad with false right button was still functionally a clickpad and merely triggered a warning. The current code changes it to a non-clickpad, effectively breaking those devices. Even if the split of false BUTTONPAD
vs false BTN_RIGHT
was 50/50, this is still the worse UX for users.
So we should revert the commit, make sure quirks are updated where needed, and upstream kernel patches for the set of devices that need quirks.
cc @jwrdegoede