[PATCH libinput] touchpad: fix double/multitap timeouts

[Bill Spitzak]

Are you saying the first event is delayed until it knows whether it is 
double-tap or not? That is not going to work, it will introduce a huge 
annoying latency to interaction.

I suspect I am misunderstanding this and an event is sent, but want to 
make sure.

On 04/30/2015 09:46 PM, Peter Hutterer wrote:
> The current doubletap timeout was incorrect, it gave the user only 180ms to
> touch, release, touch, release to recognise a doubletap. But it would also set
> a timeout on the second release, delaying the button events by 180ms.
>
> Instead, re-arm the timer on the second touch down. This gives the user 180ms
> to release and touch again (or time out). This makes doubletap much more
> reliable and reduces the delay between the release and the button events
> arriving since the finger down time is already counted.
>
> Same fix for MULTITAP, though we already armed the timer on touch down so we
> just have to remove the new timer on touch release which did little but delay
> everything.
>
> https://bugs.freedesktop.org/show_bug.cgi?id=90172
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
>   src/evdev-mt-touchpad-tap.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/src/evdev-mt-touchpad-tap.c b/src/evdev-mt-touchpad-tap.c
> index 7d1fc84..50e1512 100644
> --- a/src/evdev-mt-touchpad-tap.c
> +++ b/src/evdev-mt-touchpad-tap.c
> @@ -224,6 +224,7 @@ tp_tap_tapped_handle_event(struct tp_dispatch *tp,
>   		break;
>   	case TAP_EVENT_TOUCH:
>   		tp->tap.state = TAP_STATE_DRAGGING_OR_DOUBLETAP;
> +		tp_tap_set_timer(tp, time);
>   		break;
>   	case TAP_EVENT_TIMEOUT:
>   		tp->tap.state = TAP_STATE_IDLE;
> @@ -355,7 +356,6 @@ tp_tap_dragging_or_doubletap_handle_event(struct tp_dispatch *tp,
>   	case TAP_EVENT_RELEASE:
>   		tp->tap.state = TAP_STATE_MULTITAP;
>   		tp_tap_notify(tp, time, 1, LIBINPUT_BUTTON_STATE_RELEASED);
> -		tp_tap_set_timer(tp, time);
>   		break;
>   	case TAP_EVENT_MOTION:
>   	case TAP_EVENT_TIMEOUT:
> @@ -487,7 +487,6 @@ tp_tap_multitap_down_handle_event(struct tp_dispatch *tp,
>   	case TAP_EVENT_RELEASE:
>   		tp->tap.state = TAP_STATE_MULTITAP;
>   		tp_tap_notify(tp, time, 1, LIBINPUT_BUTTON_STATE_RELEASED);
> -		tp_tap_set_timer(tp, time);
>   		break;
>   	case TAP_EVENT_TOUCH:
>   		tp->tap.state = TAP_STATE_DRAGGING_2;
>