diff --git a/src/input.c b/src/input.c
index 15ff6ed0..c59c2697 100644
--- a/src/input.c
+++ b/src/input.c
@@ -2168,6 +2168,7 @@ WL_EXPORT void
 weston_seat_release_keyboard(struct weston_seat *seat)
 {
 	seat->keyboard_device_count--;
+	assert(seat->keyboard_device_count >= 0);
 	if (seat->keyboard_device_count == 0) {
 		weston_keyboard_set_focus(seat->keyboard, NULL);
 		weston_keyboard_cancel_grab(seat->keyboard);
diff --git a/src/libinput-device.c b/src/libinput-device.c
index 0e3f46de..8a48905f 100644
--- a/src/libinput-device.c
+++ b/src/libinput-device.c
@@ -470,7 +470,7 @@ evdev_notify_keyboard_focus(struct weston_seat *seat,
 {
 	struct wl_array keys;
 
-	if (!seat->keyboard_device_count > 0)
+	if (seat->keyboard_device_count == 0)
 		return;
 
 	wl_array_init(&keys);