Hi Ulf,

On Mon, Aug 07, 2017 at 10:14:20PM +0200, Ulf Brosziewski wrote:
| Hi Paul,
| thanks for the feedback.
| With respect to tapping, I'm already running out of hypotheses
| that can be tested without fine-grained debugging.  You might
| check whether pressure thresholds play a role, but I wouldn't be
| too optimistic about it.  You could clear them as follows:
|    # wsconsctl mouse.tp.param=2:0,3:0
| and see whether it helps.  This command restores the defaults:
|    # wsconsctl mouse.tp.param=2:25,3:30

I tried playing with this too, but unfortunately it didn't help.

| As to your observations concerning click-and-drag, I might have
| thought of that, it concerns some basics:  If you want to move
| the pointer while there are two or more contacts on the touchpad,
| which one should control the movement?  I think that's not totally
| trivial.  Linux gives a simple, but somewhat problematic answer:
| The "oldest" touch controls the pointer.  But if a driver does
| nothing else about it, this has the effect that the outcomes of
| your two-finger gestures can depend on the order in which you make
| the contacts.  You can still observe that on some Linux laptops
| when your are scrolling with two fingers, but leave one finger
| simply resting on the surface.
| In your case, it's the firmware, not the driver, that does this
| work, but the principle seems to be the same.  But how are users
| supposed to know it?  It's not evident.
| The synaptics driver adds up the differences of the coordinates
| when it receives multi-touch data, and moves the pointer by those
| "accumulated" values.  Older versions applied the method to
| click-and-drag operations, newer versions to both click-and-drag
| and two-finger scrolling.
| The wsmouse driver implements a different approach: when it
| receives multi-touch data - up to now, from Apple or Elantech-4
| models - it assigns pointer-control to touches that are moving (if
| such a touch exists).

Thanks for the detailed explanation.  I guess it's just another weird
oddity in this machine, it has a few small other nits (otherwise it's
a fine laptop).




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