Re: [PATCH] Input: elan_i2c - Change the hover event from MT to ST

From: Dmitry Torokhov
Date: Wed Jul 08 2015 - 19:12:08 EST


On Wed, Jul 08, 2015 at 06:58:36PM -0400, Benjamin Tissoires wrote:
> On Tue, Jul 7, 2015 at 2:06 PM, Dmitry Torokhov
> <dmitry.torokhov@xxxxxxxxx> wrote:
> > On Tue, Jul 07, 2015 at 01:37:14PM +0800, duson wrote:
> >> We want the hover event like BTN_LEFT, even no contract object,
> >> it still can be reported to upper OS system.
> >>
> >> Signed-off by: Duson Lin <dusonlin@xxxxxxxxxx>
> >
> > Applied, thank you.
>
> Sorry for waking up too late but I am not sure we want this patch.
>
> Why do we need to remove the ABS_MT_DISTANCE bits? I can understand
> that we would want to to have ABS_DISTANCE for the pointer emulation,
> but removing the per-finger information does not make much sense.
> libinput knows now how to deal with per-finger hovering through
> ABS_MT_DISTANCE, and you are just breaking the touchpad/screens with
> this patch.

Because the device does not provide per-finger information about
hovering. It can only tell that there is "something" hovering over the
surface, but it doe snot provide the data that there are 2 fingers
hovering or that finger 1 was in contact but now is hovering, etc.

Thanks.

--
Dmitry
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