tablet: fix double proximity out on slow proximity out pens

Where the proximity out event is delayed by the kernel, libinput would cause
an extra proxmity in-out after the forced proximity out event.

Event sequence is basically (k: kernel, l: libinput)

k: tablet axis events
l: tablet axis events
k: nothing for $proximity timer milliseconds
l: tablet proximity out
k: proximity out event
l: proximity in event
l: proximity out event

Fixes #306

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/evdev-tablet.c

@@ -806,6 +806,7 @@ tablet_process_key(struct tablet_dispatch *tablet,
 	case BTN_TOOL_MOUSE:
 	case BTN_TOOL_LENS:
 		type = tablet_evcode_to_tool(e->code);
+		tablet_set_status(tablet, TABLET_TOOL_UPDATED);
 		if (e->value)
 			tablet->tool_state |= bit(type);
 		else
@@ -1721,13 +1722,22 @@ tablet_update_tool_state(struct tablet_dispatch *tablet,
 	 *   BTN_TOOL_PEN and the state for the tool was 0, this device will
 	 *   never send the event.
 	 * We don't do this for pure button events because we discard those.
+	 *
+	 * But: on some devices the proximity out is delayed by the kernel,
+	 * so we get it after our forced prox-out has triggered. In that
+	 * case we need to just ignore the change.
 	 */
-	if (tablet_has_status(tablet, TABLET_AXES_UPDATED) &&
+	if (tablet_has_status(tablet, TABLET_AXES_UPDATED)) {
-	    (tablet->quirks.proximity_out_forced ||
+		if (tablet->quirks.proximity_out_forced) {
-	     (tablet->tool_state == 0 &&
+			if (!tablet_has_status(tablet, TABLET_TOOL_UPDATED) ||
-	      tablet->current_tool.type == LIBINPUT_TOOL_NONE))) {
+			    tablet->tool_state)
-		tablet->tool_state = bit(LIBINPUT_TABLET_TOOL_TYPE_PEN);
+				tablet->tool_state = bit(LIBINPUT_TABLET_TOOL_TYPE_PEN);
-		tablet->quirks.proximity_out_forced = false;
+			tablet->quirks.proximity_out_forced = false;
+		} else if (tablet->tool_state == 0 &&
+			    tablet->current_tool.type == LIBINPUT_TOOL_NONE) {
+			tablet->tool_state = bit(LIBINPUT_TABLET_TOOL_TYPE_PEN);
+			tablet->quirks.proximity_out_forced = false;
+		}
 	}
 
 	if (tablet->tool_state == tablet->prev_tool_state)
@@ -1886,6 +1896,7 @@ tablet_reset_state(struct tablet_dispatch *tablet)
 	memcpy(&tablet->prev_button_state,
 	       &tablet->button_state,
 	       sizeof(tablet->button_state));
+	tablet_unset_status(tablet, TABLET_TOOL_UPDATED);
 }
 
 static void

src/evdev-tablet.h

@@ -38,13 +38,14 @@ enum tablet_status {
 	TABLET_AXES_UPDATED		= bit(0),
 	TABLET_BUTTONS_PRESSED		= bit(1),
 	TABLET_BUTTONS_RELEASED		= bit(2),
-	TABLET_TOOL_IN_CONTACT		= bit(3),
+	TABLET_TOOL_UPDATED		= bit(3),
-	TABLET_TOOL_LEAVING_PROXIMITY	= bit(4),
+	TABLET_TOOL_IN_CONTACT		= bit(4),
-	TABLET_TOOL_OUT_OF_PROXIMITY	= bit(5),
+	TABLET_TOOL_LEAVING_PROXIMITY	= bit(5),
-	TABLET_TOOL_ENTERING_PROXIMITY	= bit(6),
+	TABLET_TOOL_OUT_OF_PROXIMITY	= bit(6),
-	TABLET_TOOL_ENTERING_CONTACT	= bit(7),
+	TABLET_TOOL_ENTERING_PROXIMITY	= bit(7),
-	TABLET_TOOL_LEAVING_CONTACT	= bit(8),
+	TABLET_TOOL_ENTERING_CONTACT	= bit(8),
-	TABLET_TOOL_OUT_OF_RANGE	= bit(9),
+	TABLET_TOOL_LEAVING_CONTACT	= bit(9),
+	TABLET_TOOL_OUT_OF_RANGE	= bit(10),
 };
 
 struct button_state {

test/test-tablet.c

@@ -1506,6 +1506,32 @@ START_TEST(proximity_range_button_release)
 }
 END_TEST
 
+START_TEST(proximity_out_slow_event)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+	struct axis_replacement axes[] = {
+		{ ABS_DISTANCE, 90 },
+		{ -1, -1 }
+	};
+
+	litest_tablet_proximity_in(dev, 10, 10, axes);
+	litest_tablet_motion(dev, 12, 12, axes);
+	litest_drain_events(li);
+
+	litest_timeout_tablet_proxout();
+	libinput_dispatch(li);
+
+	/* The forced prox out */
+	litest_assert_tablet_proximity_event(li,
+					     LIBINPUT_TABLET_TOOL_PROXIMITY_STATE_OUT);
+	litest_assert_empty_queue(li);
+
+	litest_tablet_proximity_out(dev);
+	litest_assert_empty_queue(li);
+}
+END_TEST
+
 START_TEST(proximity_out_on_delete)
 {
 	struct libinput *li = litest_create_context();
@@ -5651,6 +5677,8 @@ TEST_COLLECTION(tablet)
 	litest_add("tablet:proximity", proximity_range_button_click, LITEST_TABLET | LITEST_DISTANCE | LITEST_TOOL_MOUSE, LITEST_ANY);
 	litest_add("tablet:proximity", proximity_range_button_press, LITEST_TABLET | LITEST_DISTANCE | LITEST_TOOL_MOUSE, LITEST_ANY);
 	litest_add("tablet:proximity", proximity_range_button_release, LITEST_TABLET | LITEST_DISTANCE | LITEST_TOOL_MOUSE, LITEST_ANY);
+	litest_add("tablet:proximity", proximity_out_slow_event, LITEST_TABLET | LITEST_DISTANCE, LITEST_ANY);
+
 	litest_add_no_device("tablet:proximity", proximity_out_on_delete);
 	litest_add("tablet:button", button_down_up, LITEST_TABLET, LITEST_ANY);
 	litest_add("tablet:button", button_seat_count, LITEST_TABLET, LITEST_ANY);