input: Handle unplugging the output for a touchscreen device

A paired touch screen will stop sending events if its corresponding
output is unplugged.  An unpaired touchscreen will pick the new primary
output.

https://bugs.freedesktop.org/show_bug.cgi?id=73637

desktop-shell/shell.c

@@ -1795,7 +1795,7 @@ ping_timeout_handler(void *data)
 	shsurf->unresponsive = 1;
 
 	wl_list_for_each(seat, &shsurf->surface->compositor->seat_list, link)
-		if (seat->pointer && seat->pointer->focus &&
+		if (seat->pointer->focus &&
 		    seat->pointer->focus->surface == shsurf->surface)
 			set_busy_cursor(shsurf, seat->pointer);
 
@@ -5432,6 +5432,8 @@ shell_destroy(struct wl_listener *listener, void *data)
 	struct workspace **ws;
 	struct shell_output *shell_output, *tmp;
 
+	/* Force state to unlocked so we don't try to fade */
+	shell->locked = false;
 	if (shell->child.client)
 		wl_client_destroy(shell->child.client);
 

src/evdev.c

@@ -102,6 +102,8 @@ evdev_flush_pending_event(struct evdev_device *device, uint32_t time)
 		device->rel.dy = 0;
 		goto handled;
 	case EVDEV_ABSOLUTE_MT_DOWN:
+		if (device->output == NULL)
+			break;
 		weston_output_transform_coordinate(device->output,
 						   wl_fixed_from_int(device->mt.slots[slot].x),
 						   wl_fixed_from_int(device->mt.slots[slot].y),
@@ -113,6 +115,8 @@ evdev_flush_pending_event(struct evdev_device *device, uint32_t time)
 		notify_touch(master, time, seat_slot, x, y, WL_TOUCH_DOWN);
 		goto handled;
 	case EVDEV_ABSOLUTE_MT_MOTION:
+		if (device->output == NULL)
+			break;
 		weston_output_transform_coordinate(device->output,
 						   wl_fixed_from_int(device->mt.slots[slot].x),
 						   wl_fixed_from_int(device->mt.slots[slot].y),
@@ -126,6 +130,8 @@ evdev_flush_pending_event(struct evdev_device *device, uint32_t time)
 		notify_touch(master, time, seat_slot, 0, 0, WL_TOUCH_UP);
 		goto handled;
 	case EVDEV_ABSOLUTE_TOUCH_DOWN:
+		if (device->output == NULL)
+			break;
 		transform_absolute(device, &cx, &cy);
 		weston_output_transform_coordinate(device->output,
 						   wl_fixed_from_int(cx),
@@ -137,6 +143,8 @@ evdev_flush_pending_event(struct evdev_device *device, uint32_t time)
 		notify_touch(master, time, seat_slot, x, y, WL_TOUCH_DOWN);
 		goto handled;
 	case EVDEV_ABSOLUTE_MOTION:
+		if (device->output == NULL)
+			break;
 		transform_absolute(device, &cx, &cy);
 		weston_output_transform_coordinate(device->output,
 						   wl_fixed_from_int(cx),
@@ -219,8 +227,13 @@ evdev_process_touch(struct evdev_device *device,
 		    struct input_event *e,
 		    uint32_t time)
 {
-	const int screen_width = device->output->current_mode->width;
-	const int screen_height = device->output->current_mode->height;
+	int screen_width, screen_height;
+
+	if (device->output == NULL)
+		return;
+
+	screen_width = device->output->current_mode->width;
+	screen_height = device->output->current_mode->height;
 
 	switch (e->code) {
 	case ABS_MT_SLOT:
@@ -257,8 +270,13 @@ static inline void
 evdev_process_absolute_motion(struct evdev_device *device,
 			      struct input_event *e)
 {
-	const int screen_width = device->output->current_mode->width;
-	const int screen_height = device->output->current_mode->height;
+	int screen_width, screen_height;
+
+	if (device->output == NULL)
+		return;
+
+	screen_width = device->output->current_mode->width;
+	screen_height = device->output->current_mode->height;
 
 	switch (e->code) {
 	case ABS_X:
@@ -575,6 +593,34 @@ evdev_configure_device(struct evdev_device *device)
 	return 0;
 }
 
+static void
+notify_output_destroy(struct wl_listener *listener, void *data)
+{
+	struct evdev_device *device =
+		container_of(listener,
+			     struct evdev_device, output_destroy_listener);
+	struct weston_compositor *c = device->seat->compositor;
+	struct weston_output *output;
+
+	if (device->output_name) {
+		output = container_of(c->output_list.next,
+				      struct weston_output, link);
+		evdev_device_set_output(device, output);
+	} else {
+		device->output = NULL;
+	}
+}
+
+void
+evdev_device_set_output(struct evdev_device *device,
+			struct weston_output *output)
+{
+	device->output = output;
+	device->output_destroy_listener.notify = notify_output_destroy;
+	wl_signal_add(&output->destroy_signal,
+		      &device->output_destroy_listener);
+}
+
 struct evdev_device *
 evdev_device_create(struct weston_seat *seat, const char *path, int device_fd)
 {
@@ -587,9 +633,6 @@ evdev_device_create(struct weston_seat *seat, const char *path, int device_fd)
 		return NULL;
 
 	ec = seat->compositor;
-	device->output =
-		container_of(ec->output_list.next, struct weston_output, link);
-
 	device->seat = seat;
 	device->seat_caps = 0;
 	device->is_mt = 0;

src/evdev.h

@@ -53,6 +53,7 @@ struct evdev_device {
 	struct wl_event_source *source;
 	struct weston_output *output;
 	struct evdev_dispatch *dispatch;
+	struct wl_listener output_destroy_listener;
 	char *devnode;
 	char *devname;
 	char *output_name;
@@ -123,6 +124,9 @@ evdev_led_update(struct evdev_device *device, enum weston_led leds);
 struct evdev_device *
 evdev_device_create(struct weston_seat *seat, const char *path, int device_fd);
 
+void
+evdev_device_set_output(struct evdev_device *device,
+			struct weston_output *output);
 void
 evdev_device_destroy(struct evdev_device *device);
 

src/udev-seat.c

@@ -126,7 +126,11 @@ device_added(struct udev_device *udev_device, struct udev_input *input)
 		device->output_name = strdup(output_name);
 		wl_list_for_each(output, &c->output_list, link)
 			if (strcmp(output->name, device->output_name) == 0)
-				device->output = output;
+				evdev_device_set_output(device, output);
+	} else if (device->output == NULL) {
+		output = container_of(c->output_list.next,
+				      struct weston_output, link);
+		evdev_device_set_output(device, output);
 	}
 
 	if (input->enabled == 1)
@@ -354,8 +358,10 @@ notify_output_create(struct wl_listener *listener, void *data)
 
 	wl_list_for_each(device, &seat->devices_list, link)
 		if (device->output_name &&
-		    strcmp(output->name, device->output_name) == 0)
-			device->output = output;
+		    strcmp(output->name, device->output_name) == 0) {
+			evdev_device_set_output(device, output);
+			break;
+		}
 }
 
 static struct udev_seat *