[PATCH libinput] fallback: fix lid switch event listener being initialized twice

[Peter Hutterer]

Once the lid is closed, the keyboard event listener is set up to open the lid
for us on keyboard events. With the right sequence, we can trigger the
listener to be added to the list multiple times, triggering an assert in the
list test code (or an infinite loop in the 1.8 branch).

Conditions:
* SW_LID value 1 - sets up the keyboard listener
* keyboard event - sets lid_is_closed to false
* SW_LID value 0 - is ignored because we're already open
* SW_LID value 1 - sets up the keyboard listener again

https://bugs.freedesktop.org/show_bug.cgi?id=103298

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-fallback.c | 13 ++++++-------
 test/test-switch.c   | 40 +++++++++++++++++++++-------------------
 2 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/src/evdev-fallback.c b/src/evdev-fallback.c
index 13e130ac..4da07e7d 100644
--- a/src/evdev-fallback.c
+++ b/src/evdev-fallback.c
@@ -949,6 +949,8 @@ fallback_lid_toggle_keyboard_listener(struct fallback_dispatch *dispatch,
 {
 	assert(kbd->device);
 
+	libinput_device_remove_event_listener(&kbd->listener);
+
 	if (is_closed) {
 		libinput_device_add_event_listener(
 					&kbd->device->base,
@@ -956,10 +958,7 @@ fallback_lid_toggle_keyboard_listener(struct fallback_dispatch *dispatch,
 					fallback_lid_keyboard_event,
 					dispatch);
 	} else {
-		libinput_device_remove_event_listener(
-					&kbd->listener);
-		libinput_device_init_event_listener(
-					&kbd->listener);
+		libinput_device_init_event_listener(&kbd->listener);
 	}
 }
 
@@ -992,11 +991,11 @@ fallback_process_switch(struct fallback_dispatch *dispatch,
 	case SW_LID:
 		is_closed = !!e->value;
 
-		if (dispatch->lid.is_closed == is_closed)
-			return;
-
 		fallback_lid_toggle_keyboard_listeners(dispatch, is_closed);
 
+		if (dispatch->lid.is_closed == is_closed)
+			return;
+
 		dispatch->lid.is_closed = is_closed;
 		fallback_lid_notify_toggle(dispatch, device, time);
 		break;
diff --git a/test/test-switch.c b/test/test-switch.c
index 3a499bf7..d62ca9fa 100644
--- a/test/test-switch.c
+++ b/test/test-switch.c
@@ -513,30 +513,32 @@ START_TEST(lid_open_on_key)
 
 	keyboard = litest_add_device(li, LITEST_KEYBOARD);
 
-	litest_switch_action(sw,
-			     LIBINPUT_SWITCH_LID,
-			     LIBINPUT_SWITCH_STATE_ON);
-	litest_drain_events(li);
+	for (int i = 0; i < 3; i++) {
+		litest_switch_action(sw,
+				     LIBINPUT_SWITCH_LID,
+				     LIBINPUT_SWITCH_STATE_ON);
+		litest_drain_events(li);
 
-	litest_event(keyboard, EV_KEY, KEY_A, 1);
-	litest_event(keyboard, EV_SYN, SYN_REPORT, 0);
-	litest_event(keyboard, EV_KEY, KEY_A, 0);
-	litest_event(keyboard, EV_SYN, SYN_REPORT, 0);
-	libinput_dispatch(li);
+		litest_event(keyboard, EV_KEY, KEY_A, 1);
+		litest_event(keyboard, EV_SYN, SYN_REPORT, 0);
+		litest_event(keyboard, EV_KEY, KEY_A, 0);
+		litest_event(keyboard, EV_SYN, SYN_REPORT, 0);
+		libinput_dispatch(li);
 
-	event = libinput_get_event(li);
-	litest_is_switch_event(event,
-			       LIBINPUT_SWITCH_LID,
-			       LIBINPUT_SWITCH_STATE_OFF);
+		event = libinput_get_event(li);
+		litest_is_switch_event(event,
+				       LIBINPUT_SWITCH_LID,
+				       LIBINPUT_SWITCH_STATE_OFF);
+		libinput_event_destroy(event);
 
-	litest_assert_only_typed_events(li, LIBINPUT_EVENT_KEYBOARD_KEY);
+		litest_assert_only_typed_events(li, LIBINPUT_EVENT_KEYBOARD_KEY);
 
-	litest_switch_action(sw,
-			     LIBINPUT_SWITCH_LID,
-			     LIBINPUT_SWITCH_STATE_OFF);
-	litest_assert_empty_queue(li);
+		litest_switch_action(sw,
+				     LIBINPUT_SWITCH_LID,
+				     LIBINPUT_SWITCH_STATE_OFF);
+		litest_assert_empty_queue(li);
+	}
 
-	libinput_event_destroy(event);
 	litest_delete_device(keyboard);
 }
 END_TEST
-- 
2.13.6