touchpad: add touch-size based touch handling

Apple touchpads don't use ABS_MT_PRESSURE but they are multitouch touchpads,
so the current pressure-based handling code doesn't apply because it expects
slot-based pressure for mt touchpads.

Apple does however send useful data for ABS_MT_WIDTH_MAJOR/MINOR, so let's use
that instead. The data provided in those is more-or-less random, so we need a
hwdb entry to track the acceptable thresholds.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/evdev-mt-touchpad.c

@@ -348,6 +348,16 @@ tp_process_absolute(struct tp_dispatch *tp,
 		t->dirty = true;
 		tp->queued |= TOUCHPAD_EVENT_OTHERAXIS;
 		break;
+	case ABS_MT_TOUCH_MAJOR:
+		t->major = e->value;
+		t->dirty = true;
+		tp->queued |= TOUCHPAD_EVENT_OTHERAXIS;
+		break;
+	case ABS_MT_TOUCH_MINOR:
+		t->minor = e->value;
+		t->dirty = true;
+		tp->queued |= TOUCHPAD_EVENT_OTHERAXIS;
+		break;
 	}
 }
 
@@ -1015,6 +1025,45 @@ tp_unhover_pressure(struct tp_dispatch *tp, uint64_t time)
 	}
 }
 
+static void
+tp_unhover_size(struct tp_dispatch *tp, uint64_t time)
+{
+	struct tp_touch *t;
+	int low = tp->touch_size.low,
+	    high = tp->touch_size.high;
+	int i;
+
+	/* We require 5 slots for size handling, so we don't need to care
+	 * about fake touches here */
+
+	for (i = 0; i < (int)tp->num_slots; i++) {
+		t = tp_get_touch(tp, i);
+
+		if (t->state == TOUCH_NONE)
+			continue;
+
+		if (!t->dirty)
+			continue;
+
+		if (t->state == TOUCH_HOVERING) {
+			if ((t->major > high && t->minor > low) ||
+			    (t->major > low && t->minor > high)) {
+				evdev_log_debug(tp->device,
+						"touch-size: begin touch\n");
+				/* avoid jumps when landing a finger */
+				tp_motion_history_reset(t);
+				tp_begin_touch(tp, t, time);
+			}
+		} else {
+			if (t->major < low || t->minor < low) {
+				evdev_log_debug(tp->device,
+						"touch-size: end touch\n");
+				tp_end_touch(tp, t, time);
+			}
+		}
+	}
+}
+
 static void
 tp_unhover_fake_touches(struct tp_dispatch *tp, uint64_t time)
 {
@@ -1077,6 +1126,8 @@ tp_unhover_touches(struct tp_dispatch *tp, uint64_t time)
 {
 	if (tp->pressure.use_pressure)
 		tp_unhover_pressure(tp, time);
+	else if (tp->touch_size.use_touch_size)
+		tp_unhover_size(tp, time);
 	else
 		tp_unhover_fake_touches(tp, time);
 
@@ -1512,6 +1563,15 @@ tp_sync_touch(struct tp_dispatch *tp,
 		t->pressure = libevdev_get_event_value(evdev,
 						       EV_ABS,
 						       ABS_PRESSURE);
+
+	libevdev_fetch_slot_value(evdev,
+				  slot,
+				  ABS_MT_TOUCH_MAJOR,
+				  &t->major);
+	libevdev_fetch_slot_value(evdev,
+				  slot,
+				  ABS_MT_TOUCH_MINOR,
+				  &t->minor);
 }
 
 static void
@@ -2650,10 +2710,59 @@ tp_init_pressure(struct tp_dispatch *tp,
 			"using pressure-based touch detection\n");
 }
 
+static bool
+tp_init_touch_size(struct tp_dispatch *tp,
+		   struct evdev_device *device)
+{
+	const char *prop;
+	int lo, hi;
+
+	if (!libevdev_has_event_code(device->evdev,
+				     EV_ABS,
+				     ABS_MT_TOUCH_MAJOR)) {
+		return false;
+	}
+
+	if (libevdev_get_num_slots(device->evdev) < 5) {
+		evdev_log_bug_libinput(device,
+			       "Expected 5+ slots for touch size detection\n");
+		return false;
+	}
+
+	prop = udev_device_get_property_value(device->udev_device,
+					      "LIBINPUT_ATTR_TOUCH_SIZE_RANGE");
+	if (!prop)
+		return false;
+
+	if (!parse_range_property(prop, &hi, &lo)) {
+		evdev_log_bug_client(device,
+				     "discarding invalid touch size range '%s'\n",
+				     prop);
+		return false;
+	}
+
+	if (hi == 0 && lo == 0) {
+		evdev_log_info(device,
+			       "touch size based touch detection disabled\n");
+		return false;
+	}
+
+	/* Thresholds apply for both major or minor */
+	tp->touch_size.low = lo;
+	tp->touch_size.high = hi;
+	tp->touch_size.use_touch_size = true;
+
+	evdev_log_debug(device, "using size-based touch detection\n");
+
+	return true;
+}
+
 static int
 tp_init(struct tp_dispatch *tp,
 	struct evdev_device *device)
 {
+	bool use_touch_size = false;
+
 	tp->base.dispatch_type = DISPATCH_TOUCHPAD;
 	tp->base.interface = &tp_interface;
 	tp->device = device;
@@ -2668,7 +2777,11 @@ tp_init(struct tp_dispatch *tp,
 
 	evdev_device_init_abs_range_warnings(device);
 
-	tp_init_pressure(tp, device);
+	if (device->model_flags & EVDEV_MODEL_APPLE_TOUCHPAD)
+		use_touch_size = tp_init_touch_size(tp, device);
+
+	if (!use_touch_size)
+		tp_init_pressure(tp, device);
 
 	/* Set the dpi to that of the x axis, because that's what we normalize
 	   to when needed*/

src/evdev-mt-touchpad.h

@@ -148,6 +148,7 @@ struct tp_touch {
 	uint64_t time;
 	int pressure;
 	bool is_tool_palm; /* MT_TOOL_PALM */
+	int major, minor;
 
 	bool was_down; /* if distance == 0, false for pure hovering
 			  touches */
@@ -248,6 +249,17 @@ struct tp_dispatch {
 		int low;
 	} pressure;
 
+	/* If touch size (either axis) goes above high -> touch down,
+	   if touch size (either axis) goes below low -> touch up */
+	struct  {
+		bool use_touch_size;
+		int high;
+		int low;
+
+		/* convert device units to angle */
+		double orientation_to_angle;
+	} touch_size;
+
 	struct device_coords hysteresis_margin;
 
 	struct {

src/evdev.c

@@ -1896,7 +1896,7 @@ evdev_process_event(struct evdev_device *device, struct input_event *e)
 	struct evdev_dispatch *dispatch = device->dispatch;
 	uint64_t time = tv2us(&e->time);
 
-#if 0
+#if 1
 	if (libevdev_event_is_code(e, EV_SYN, SYN_REPORT))
 		evdev_log_debug(device,
 			  "-------------- EV_SYN ------------\n");

test/litest-device-bcm5974.c

@@ -40,6 +40,9 @@ static struct input_event down[] = {
 	{ .type = EV_ABS, .code = ABS_MT_TRACKING_ID, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_X, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_Y, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_ORIENTATION, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_SYN, .code = SYN_REPORT, .value = 0 },
 	{ .type = -1, .code = -1 },
 };
@@ -51,6 +54,9 @@ static struct input_event move[] = {
 	{ .type = EV_ABS, .code = ABS_PRESSURE, .value = LITEST_AUTO_ASSIGN  },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_X, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_Y, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_ORIENTATION, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_SYN, .code = SYN_REPORT, .value = 0 },
 	{ .type = -1, .code = -1 },
 };
@@ -63,6 +69,12 @@ get_axis_default(struct litest_device *d, unsigned int evcode, int32_t *value)
 	case ABS_MT_PRESSURE:
 		*value = 30;
 		return 0;
+	case ABS_MT_TOUCH_MAJOR:
+	case ABS_MT_TOUCH_MINOR:
+		*value = 200;
+		return 0;
+	case ABS_MT_ORIENTATION:
+		return 0;
 	}
 	return 1;
 }

test/litest-device-magic-trackpad.c

@@ -37,10 +37,11 @@ static struct input_event down[] = {
 	{ .type = EV_ABS, .code = ABS_Y, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_SLOT, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_TRACKING_ID, .value = LITEST_AUTO_ASSIGN },
-	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = 272 },
-	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = 400 },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_X, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_Y, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_ORIENTATION, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_SYN, .code = SYN_REPORT, .value = 0 },
 	{ .type = -1, .code = -1 },
 };
@@ -49,17 +50,34 @@ static struct input_event move[] = {
 	{ .type = EV_ABS, .code = ABS_MT_SLOT, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_X, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_Y, .value = LITEST_AUTO_ASSIGN },
-	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = 272 },
-	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = 400 },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MAJOR, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_TOUCH_MINOR, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_X, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_ABS, .code = ABS_MT_POSITION_Y, .value = LITEST_AUTO_ASSIGN },
+	{ .type = EV_ABS, .code = ABS_MT_ORIENTATION, .value = LITEST_AUTO_ASSIGN },
 	{ .type = EV_SYN, .code = SYN_REPORT, .value = 0 },
 	{ .type = -1, .code = -1 },
 };
 
+static int
+get_axis_default(struct litest_device *d, unsigned int evcode, int32_t *value)
+{
+	switch (evcode) {
+	case ABS_MT_TOUCH_MAJOR:
+	case ABS_MT_TOUCH_MINOR:
+		*value = 200;
+		return 0;
+	case ABS_MT_ORIENTATION:
+		return 0;
+	}
+	return 1;
+}
+
 static struct litest_device_interface interface = {
 	.touch_down_events = down,
 	.touch_move_events = move,
+
+	.get_axis_default = get_axis_default,
 };
 
 static struct input_absinfo absinfo[] = {

test/test-touchpad.c

@@ -5273,6 +5273,109 @@ START_TEST(touchpad_pressure_tap_2fg_1fg_light)
 }
 END_TEST
 
+static inline bool
+touchpad_has_touch_size(struct litest_device *dev)
+{
+	struct libevdev *evdev = dev->evdev;
+
+	if (!libevdev_has_event_code(evdev, EV_ABS, ABS_MT_TOUCH_MAJOR))
+		return false;
+
+	if (libevdev_get_id_vendor(evdev) == VENDOR_ID_APPLE)
+		return true;
+
+	return false;
+}
+
+START_TEST(touchpad_touch_size)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+	struct axis_replacement axes[] = {
+		{ ABS_MT_TOUCH_MAJOR, 0 },
+		{ ABS_MT_TOUCH_MINOR, 0 },
+		{ ABS_MT_ORIENTATION, 0 },
+		{ -1, 0 }
+	};
+
+	if (!touchpad_has_touch_size(dev))
+		return;
+
+	litest_drain_events(li);
+
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MAJOR, 1);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MINOR, 1);
+	litest_touch_down_extended(dev, 0, 50, 50, axes);
+	litest_touch_move_to_extended(dev, 0,
+				      50, 50,
+				      80, 80,
+				      axes, 10, 1);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MAJOR, 15);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MINOR, 15);
+	litest_touch_down_extended(dev, 0, 50, 50, axes);
+	litest_touch_move_to_extended(dev, 0,
+				      50, 50,
+				      80, 80,
+				      axes, 10, 1);
+	litest_touch_up(dev, 0);
+	litest_assert_only_typed_events(li,
+					LIBINPUT_EVENT_POINTER_MOTION);
+}
+END_TEST
+
+START_TEST(touchpad_touch_size_2fg)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+	struct axis_replacement axes[] = {
+		{ ABS_MT_TOUCH_MAJOR, 0 },
+		{ ABS_MT_TOUCH_MINOR, 0 },
+		{ ABS_MT_ORIENTATION, 0 },
+		{ -1, 0 }
+	};
+
+	if (!touchpad_has_touch_size(dev))
+		return;
+
+	litest_drain_events(li);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MAJOR, 15);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MINOR, 15);
+	litest_touch_down_extended(dev, 0, 50, 50, axes);
+	litest_touch_move_to_extended(dev, 0,
+				      50, 50,
+				      80, 80,
+				      axes, 10, 1);
+
+	litest_assert_only_typed_events(li,
+					LIBINPUT_EVENT_POINTER_MOTION);
+
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MAJOR, 1);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MINOR, 1);
+	litest_touch_down_extended(dev, 1, 70, 70, axes);
+	litest_touch_move_to_extended(dev, 1,
+				      70, 70,
+				      80, 90,
+				      axes, 10, 1);
+	litest_assert_empty_queue(li);
+
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MAJOR, 15);
+	litest_axis_set_value(axes, ABS_MT_TOUCH_MINOR, 15);
+	litest_touch_move_to_extended(dev, 0,
+				      80, 80,
+				      50, 50,
+				      axes, 10, 1);
+
+	litest_assert_only_typed_events(li,
+					LIBINPUT_EVENT_POINTER_MOTION);
+
+	litest_touch_up(dev, 1);
+	litest_touch_up(dev, 0);
+}
+END_TEST
+
 void
 litest_setup_tests_touchpad(void)
 {
@@ -5434,4 +5537,7 @@ litest_setup_tests_touchpad(void)
 	litest_add("touchpad:pressure", touchpad_pressure_tap, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:pressure", touchpad_pressure_tap_2fg, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:pressure", touchpad_pressure_tap_2fg_1fg_light, LITEST_TOUCHPAD, LITEST_ANY);
+
+	litest_add("touchpad:touch-size", touchpad_touch_size, LITEST_APPLE_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:touch-size", touchpad_touch_size_2fg, LITEST_APPLE_CLICKPAD, LITEST_ANY);
 }

udev/90-libinput-model-quirks.hwdb

@@ -50,6 +50,7 @@ libinput:touchpad:input:b0003v05ACp*
 libinput:touchpad:input:b0005v05ACp*
  LIBINPUT_MODEL_APPLE_TOUCHPAD=1
  LIBINPUT_ATTR_SIZE_HINT=104x75
+ LIBINPUT_ATTR_TOUCH_SIZE_RANGE=150:130
 
 libinput:name:*Apple Inc. Apple Internal Keyboard*:dmi:*
  LIBINPUT_ATTR_KEYBOARD_INTEGRATION=internal

udev/parse_hwdb.py

@@ -108,6 +108,7 @@ def property_grammar():
         ('LIBINPUT_ATTR_SIZE_HINT', Group(dimension('SETTINGS*'))),
         ('LIBINPUT_ATTR_RESOLUTION_HINT', Group(dimension('SETTINGS*'))),
         ('LIBINPUT_ATTR_PRESSURE_RANGE', Group(crange('SETTINGS*'))),
+        ('LIBINPUT_ATTR_TOUCH_SIZE_RANGE', Group(crange('SETTINGS*'))),
         ('LIBINPUT_ATTR_TPKBCOMBO_LAYOUT', Or(('below'))),
         ('LIBINPUT_ATTR_LID_SWITCH_RELIABILITY',
          Or(('reliable', 'write_open'))),