[PATCH libinput] touchpad: disable MT for elantech semi-mt touchpads

[Hans de Goede]

Hi,

On 13-01-16 05:09, Peter Hutterer wrote:
> When three fingers are set down on the touchpad, one finger tends to get a 0/0
> coordinate, triggering palm detection in the upper left corner. Handle this
> like the jumping semi-mt touchpads and disable MT handling and instead
> just rely on the x/y axis and the BTN_TOOL_* events.
>
> https://bugs.freedesktop.org/show_bug.cgi?id=93583
>
> This kernel patch is required:
> https://lkml.org/lkml/2016/1/11/171
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>

Patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede at redhat.com>

About Benjamin's patch:

https://lkml.org/lkml/2016/1/11/171

Benjamin, when you pass in INPUT_MT_SEMI_MT, you can drop the:

	__set_bit(INPUT_PROP_SEMI_MT, dev->propbit);

A few lines up, since input_mt_init_slots will do that now.

More in general the elantech driver could do with some cleanup
to fully use the input_mt helpers, specifically stop doing
pointer emulation itself for v2 and v3 touchpads:
- pass in INPUT_MT_POINTER to input_mt_init_slots and stop initializing
   ABS_X / ABS_Y and move input_mt_init_slots to after setting up the MT
   axis (this applies to v4 too)
- Stop reporting BTN_TOUCH / ABS_X / ABSY in diy style instead just call
   input_mt_frame_sync before input_sync
- Replace:
         input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
         input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
         input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
         input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
   With:
	input_mt_report_finger_count(dev, fingers);
- And for v4 touchpads replace:
	input_mt_report_pointer_emulation(dev, true);
   With:
         input_mt_frame_sync(dev);
   Which ends up doing the same, but is the right way to use the
   input_mt helpers

Regards,

Hans







> ---
>   src/evdev-mt-touchpad.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
> index 2de2539..f91f839 100644
> --- a/src/evdev-mt-touchpad.c
> +++ b/src/evdev-mt-touchpad.c
> @@ -1496,7 +1496,8 @@ tp_init_slots(struct tp_dispatch *tp,
>   	 * explanation.
>   	 */
>   	if (tp->semi_mt &&
> -	    (device->model_flags & EVDEV_MODEL_JUMPING_SEMI_MT)) {
> +	    (device->model_flags &
> +	     (EVDEV_MODEL_JUMPING_SEMI_MT|EVDEV_MODEL_ELANTECH_TOUCHPAD))) {
>   		tp->num_slots = 1;
>   		tp->slot = 0;
>   		tp->has_mt = false;
>