base-bearer: stop connection status monitoring if no TTY available

On modems with a single TTY for both control and data, we cannot use
the TTY to load connection status once we're in connected mode:

    Connection through a plain serial AT port (ttyUSB2)
    (ttyUSB2): --> 'ATD*99***2#<CR>'
    (ttyUSB2): <-- '<CR><LF>CONNECT 100000000<CR><LF>'
    (ttyUSB2): port now connected
    Connected bearer '/org/freedesktop/ModemManager1/Bearer/0'
    Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connecting -> connected)
    Simple connect state (8/8): All done
    checking if connected failed: Couldn't check current list of active PDP contexts: No AT port available to run command
    checking if connected failed: Couldn't check current list of active PDP contexts: No AT port available to run command
    checking if connected failed: Couldn't check current list of active PDP contexts: No AT port available to run command
    ...

So, disable connection monitoring right away if that situation is
detected:

    Connection through a plain serial AT port (ttyUSB2)
    (ttyUSB2): --> 'ATD*99***2#<CR>'
    (ttyUSB2): <-- '<CR><LF>CONNECT 100000000<CR><LF>'
    (ttyUSB2): port now connected
    Connected bearer '/org/freedesktop/ModemManager1/Bearer/0'
    Modem /org/freedesktop/ModemManager1/Modem/0: state changed (connecting -> connected)
    Simple connect state (8/8): All done
    Connection monitoring is unsupported by the device
    ...

https://bugs.freedesktop.org/show_bug.cgi?id=100376

1 files changed, 28 insertions, 13 deletions

diff --git a/src/mm-broadband-bearer.c b/src/mm-broadband-bearer.c
index 3a82defa..9491f5a8 100644
--- a/src/mm-broadband-bearer.c
+++ b/src/mm-broadband-bearer.c
@@ -1992,30 +1992,45 @@ load_connection_status (MMBaseBearer        *self,
                         GAsyncReadyCallback  callback,
                         gpointer             user_data)
 {
-    GTask       *task;
-    MMBaseModem *modem = NULL;
+    GTask          *task;
+    MMBaseModem    *modem = NULL;
+    MMPortSerialAt *port;
 
     task = g_task_new (self, NULL, callback, user_data);
 
+    g_object_get (MM_BASE_BEARER (self),
+                  MM_BASE_BEARER_MODEM, &modem,
+                  NULL);
+
+    /* If CID not defined, error out */
     if (!MM_BROADBAND_BEARER (self)->priv->cid) {
         g_task_return_new_error (task, MM_CORE_ERROR, MM_CORE_ERROR_FAILED,
                                  "Couldn't load connection status: cid not defined");
         g_object_unref (task);
-        return;
+        goto out;
     }
 
-    g_object_get (MM_BASE_BEARER (self),
-                  MM_BASE_BEARER_MODEM, &modem,
-                  NULL);
+    /* If no control port available, error out */
+    port = mm_base_modem_peek_best_at_port (modem, NULL);
+    if (!port) {
+        g_task_return_new_error (task, MM_CORE_ERROR, MM_CORE_ERROR_UNSUPPORTED,
+                                 "Couldn't load connection status: no control port available");
+        g_object_unref (task);
+        goto out;
+    }
 
-    mm_base_modem_at_command (MM_BASE_MODEM (modem),
-                              "+CGACT?",
-                              3,
-                              FALSE,
-                              (GAsyncReadyCallback) cgact_periodic_query_ready,
-                              task);
+    mm_base_modem_at_command_full (MM_BASE_MODEM (modem),
+                                   port,
+                                   "+CGACT?",
+                                   3,
+                                   FALSE, /* allow cached */
+                                   FALSE, /* raw */
+                                   NULL, /* cancellable */
+                                   (GAsyncReadyCallback) cgact_periodic_query_ready,
+                                   task);
 
-    g_object_unref (modem);
+out:
+    g_clear_object (&modem);
 }
 
 /*****************************************************************************/