broadband-modem: don't assert if no AT port in QMI modem enabling unsolicited messages

  2023-09-11T20:23:49.294555Z <err> mm_port_get_device: assertion 'self != NULL' failed
  2023-09-11T20:23:49.294691Z <dbg> [modem0] enabling messaging unsolicited events on primary port (null)
  2023-09-11T20:23:49.294865Z <dbg> [modem0] enabling parent messaging unsolicited events failed: Cannot run sequence: port not given

1 files changed, 9 insertions, 0 deletions

diff --git a/src/mm-broadband-modem.c b/src/mm-broadband-modem.c
index d3892456..01a73ba6 100644
--- a/src/mm-broadband-modem.c
+++ b/src/mm-broadband-modem.c
@@ -7412,6 +7412,15 @@ modem_messaging_enable_unsolicited_events (MMIfaceModemMessaging *self,
     task = g_task_new (self, NULL, callback, user_data);
     primary = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
 
+    /* Do nothing if the modem doesn't have any AT port (e.g. it could be
+     * a QMI modem trying to enable the parent unsolicited messages) */
+    if (!primary) {
+        g_task_return_new_error (task, MM_CORE_ERROR, MM_CORE_ERROR_FAILED,
+                                 "No AT port to enable messaging unsolicited events");
+        g_object_unref (task);
+        return;
+    }
+
     /* Enable unsolicited events for primary port */
     mm_obj_dbg (self, "enabling messaging unsolicited events on primary port %s",
                 mm_port_get_device (MM_PORT (primary)));