• Peter Hutterer's avatar
    touchpad: add pressure-base palm detection · 25d54b90
    Peter Hutterer authored
    If a touch goes past the fixed pressure threshold it is labelled as a palm and
    stays a palm. Default value is one that works well here on a T440 and is
    virtually impossible to trigger by a normal finger or thumb. A udev property
    is exposed so we can handle this in the udev hwdb and the new tool introduce a
    few commits ago can help finding the palm detection threshold.
    
    Unlike the other palm detection features, once a palm goes past the threshold
    it remains a palm until the touch is released. This means palm overrides any
    other palm detection features. For code simplicity, we don't combine the
    states but merely check for pressure before and after the other palm detection
    functions. If the pressure triggers, it will trigger before anything else. And
    if something else is already active (e.g. edge where the pressure doesn't work
    well) it will trigger as soon as the palm is released.
    
    The palm threshold should thus be chosen with some room to spare between the
    highest finger pressure.
    
    https://bugs.freedesktop.org/show_bug.cgi?id=94236Signed-off-by: Peter Hutterer's avatarPeter Hutterer <peter.hutterer@who-t.net>
    25d54b90
evdev-mt-touchpad.h 14 KB