Merge branch 'wip/touchpad-hysteresis-issues-v2'

src/evdev-mt-touchpad.c

@@ -131,6 +131,21 @@ tp_motion_history_push(struct tp_touch *t)
 	t->history.index = motion_index;
 }
 
+static inline void
+tp_maybe_disable_hysteresis(struct tp_dispatch *tp, uint64_t time)
+{
+	/* If the finger is down for 80ms without seeing motion events,
+	   the firmware filters and we don't need a software hysteresis */
+	if (time - tp->hysteresis.last_motion_time > ms2us(80)) {
+		tp->hysteresis.enabled = false;
+		evdev_log_debug(tp->device, "hysteresis disabled\n");
+		return;
+	}
+
+	if (tp->queued & TOUCHPAD_EVENT_MOTION)
+		tp->hysteresis.last_motion_time = time;
+}
+
 static inline void
 tp_motion_hysteresis(struct tp_dispatch *tp,
 		     struct tp_touch *t)
@@ -138,15 +153,18 @@ tp_motion_hysteresis(struct tp_dispatch *tp,
 	int x = t->point.x,
 	    y = t->point.y;
 
+	if (!tp->hysteresis.enabled)
+		return;
+
 	if (t->history.count == 0) {
 		t->hysteresis_center = t->point;
 	} else {
 		x = evdev_hysteresis(x,
 				     t->hysteresis_center.x,
-				     tp->hysteresis_margin.x);
+				     tp->hysteresis.margin.x);
 		y = evdev_hysteresis(y,
 				     t->hysteresis_center.y,
-				     tp->hysteresis_margin.y);
+				     tp->hysteresis.margin.y);
 		t->hysteresis_center.x = x;
 		t->hysteresis_center.y = y;
 		t->point.x = x;
@@ -273,6 +291,7 @@ tp_begin_touch(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 	t->thumb.first_touch_time = time;
 	t->tap.is_thumb = false;
 	assert(tp->nfingers_down >= 1);
+	tp->hysteresis.last_motion_time = time;
 }
 
 /**
@@ -1526,6 +1545,9 @@ static void
 tp_handle_state(struct tp_dispatch *tp,
 		uint64_t time)
 {
+	if (tp->hysteresis.enabled)
+		tp_maybe_disable_hysteresis(tp, time);
+
 	tp_process_state(tp, time);
 	tp_post_events(tp, time);
 	tp_post_process_state(tp, time);
@@ -2912,8 +2934,9 @@ tp_init_hysteresis(struct tp_dispatch *tp)
 
 	res_x = tp->device->abs.absinfo_x->resolution;
 	res_y = tp->device->abs.absinfo_y->resolution;
-	tp->hysteresis_margin.x = res_x/2;
-	tp->hysteresis_margin.y = res_y/2;
+	tp->hysteresis.margin.x = res_x/2;
+	tp->hysteresis.margin.y = res_y/2;
+	tp->hysteresis.enabled = true;
 }
 
 static void

src/evdev-mt-touchpad.h

@@ -269,7 +269,12 @@ struct tp_dispatch {
 		double orientation_to_angle;
 	} touch_size;
 
-	struct device_coords hysteresis_margin;
+	struct {
+		bool enabled;
+		struct device_coords margin;
+		unsigned int other_event_count;
+		uint64_t last_motion_time;
+	} hysteresis;
 
 	struct {
 		double x_scale_coeff;

src/evdev.h

@@ -610,6 +610,19 @@ evdev_to_left_handed(struct evdev_device *device,
  * calculation to do circular hysteresis are nontrivial, especially since
  * many touchpads have uneven x/y resolutions.
  *
+ * Given coordinates, 0, 1, 2, ... this is what we return for a margin of 3
+ * and a center of 0:
+ *
+ * Input:  1 2 3 4 5 6 5 4 3 2 1 0 -1
+ * Coord:  0 0 0 1 2 3 3 3 3 3 3 3 2
+ * Center: 0 0 0 1 2 3 3 3 3 3 3 3 2
+ *
+ * Problem: viewed from a stationary finger that starts moving, the
+ * hysteresis margin is M in both directions. Once we start moving
+ * continuously though, the margin is 0 in the movement direction and 2*M to
+ * change direction. That makes the finger less responsive to directional
+ * changes than to the original movement.
+ *
  * @param in The input coordinate
  * @param center Current center of the hysteresis
  * @param margin Hysteresis width (on each side)

test/litest.c

@@ -3239,6 +3239,12 @@ litest_timeout_tablet_proxout(void)
 	msleep(70);
 }
 
+void
+litest_timeout_hysteresis(void)
+{
+	msleep(90);
+}
+
 void
 litest_push_event_frame(struct litest_device *dev)
 {

test/litest.h

@@ -766,6 +766,9 @@ litest_timeout_trackpoint(void);
 void
 litest_timeout_tablet_proxout(void);
 
+void
+litest_timeout_hysteresis(void);
+
 void
 litest_push_event_frame(struct litest_device *dev);