[PATCH libinput 03/11] touchpad: ignore hovering touches when tapping

[Peter Hutterer]

We need to remember whether a tap was down or just hovering, otherwise we mess
up the state machine when we send tap release events for taps that never
switched to TOUCH_BEGIN. This is quick fix, really we should have a new state
here, but that's a lot harder to implement.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad-tap.c |  6 +++++-
 src/evdev-mt-touchpad.c     |  2 ++
 src/evdev-mt-touchpad.h     |  3 +++
 test/test-touchpad.c        | 19 +++++++++++++++++++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/evdev-mt-touchpad-tap.c b/src/evdev-mt-touchpad-tap.c
index 9fba521..c163599 100644
--- a/src/evdev-mt-touchpad-tap.c
+++ b/src/evdev-mt-touchpad-tap.c
@@ -774,6 +774,9 @@ tp_tap_handle_state(struct tp_dispatch *tp, uint64_t time)
 		if (t->tap.is_thumb)
 			continue;
 
+		if (t->state == TOUCH_HOVERING)
+			continue;
+
 		if (t->state == TOUCH_BEGIN) {
 			/* The simple version: if a touch is a thumb on
 			 * begin we ignore it. All other thumb touches
@@ -795,7 +798,8 @@ tp_tap_handle_state(struct tp_dispatch *tp, uint64_t time)
 				tp_tap_handle_event(tp, t, TAP_EVENT_MOTION, time);
 
 		} else if (t->state == TOUCH_END) {
-			tp_tap_handle_event(tp, t, TAP_EVENT_RELEASE, time);
+			if (t->was_down)
+				tp_tap_handle_event(tp, t, TAP_EVENT_RELEASE, time);
 			t->tap.state = TAP_TOUCH_STATE_IDLE;
 		} else if (tp->tap.state != TAP_STATE_IDLE &&
 			   tp_tap_exceeds_motion_threshold(tp, t)) {
diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index 56822df..a47c59f 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -214,6 +214,7 @@ tp_new_touch(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 	tp_motion_history_reset(t);
 	t->dirty = true;
 	t->has_ended = false;
+	t->was_down = false;
 	t->state = TOUCH_HOVERING;
 	t->pinned.is_pinned = false;
 	t->millis = time;
@@ -226,6 +227,7 @@ tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 	t->dirty = true;
 	t->state = TOUCH_BEGIN;
 	t->millis = time;
+	t->was_down = true;
 	tp->nfingers_down++;
 	t->palm.time = time;
 	t->thumb.state = THUMB_STATE_MAYBE;
diff --git a/src/evdev-mt-touchpad.h b/src/evdev-mt-touchpad.h
index fb15956..abe885f 100644
--- a/src/evdev-mt-touchpad.h
+++ b/src/evdev-mt-touchpad.h
@@ -156,6 +156,9 @@ struct tp_touch {
 	int distance;				/* distance == 0 means touch */
 	int pressure;
 
+	bool was_down; /* if distance == 0, false for pure hovering
+			  touches */
+
 	struct {
 		/* A quirk mostly used on Synaptics touchpads. In a
 		   transition to/from fake touches > num_slots, the current
diff --git a/test/test-touchpad.c b/test/test-touchpad.c
index ee8cd7f..b8ca0b9 100644
--- a/test/test-touchpad.c
+++ b/test/test-touchpad.c
@@ -2152,6 +2152,24 @@ START_TEST(touchpad_hover_2fg_1fg_down)
 }
 END_TEST
 
+START_TEST(touchpad_hover_1fg_tap)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	litest_enable_tap(dev->libinput_device);
+
+	litest_drain_events(li);
+
+	litest_hover_start(dev, 0, 50, 50);
+	litest_hover_end(dev, 0);
+
+	libinput_dispatch(li);
+	litest_assert_empty_queue(li);
+
+}
+END_TEST
+
 static void
 assert_btnevent_from_device(struct litest_device *device,
 			    unsigned int button,
@@ -4740,6 +4758,7 @@ litest_setup_tests_touchpad(void)
 	litest_add("touchpad:hover", touchpad_hover_down_hover_down, LITEST_TOUCHPAD|LITEST_HOVER, LITEST_ANY);
 	litest_add("touchpad:hover", touchpad_hover_2fg_noevent, LITEST_TOUCHPAD|LITEST_HOVER, LITEST_ANY);
 	litest_add("touchpad:hover", touchpad_hover_2fg_1fg_down, LITEST_TOUCHPAD|LITEST_HOVER, LITEST_ANY);
+	litest_add("touchpad:hover", touchpad_hover_1fg_tap, LITEST_TOUCHPAD|LITEST_HOVER, LITEST_ANY);
 
 	litest_add_for_device("touchpad:trackpoint", touchpad_trackpoint_buttons, LITEST_SYNAPTICS_TRACKPOINT_BUTTONS);
 	litest_add_for_device("touchpad:trackpoint", touchpad_trackpoint_mb_scroll, LITEST_SYNAPTICS_TRACKPOINT_BUTTONS);
-- 
2.9.3