nokia: use E1 E0 when initializing the modem

Passing E1 and E0 afterwards seems to properly disable the echo in Nokia modems
(N900 and C7 at least)

plugins/mm-modem-nokia.c

@@ -120,6 +120,11 @@ get_property (GObject *object, guint prop_id,
     case MM_GENERIC_GSM_PROP_POWER_DOWN_CMD:
         g_value_set_string (value, "");
         break;
+    case MM_GENERIC_GSM_PROP_INIT_CMD:
+        /* When initializing a Nokia phone, first enable the echo,
+         * and then disable it, so that we get it properly disabled */
+        g_value_set_string (value, "Z E1 E0 V1");
+        break;
     default:
         break;
     }
@@ -135,6 +140,10 @@ mm_modem_nokia_class_init (MMModemNokiaClass *klass)
     object_class->get_property = get_property;
     object_class->set_property = set_property;
 
+    g_object_class_override_property (object_class,
+                                      MM_GENERIC_GSM_PROP_INIT_CMD,
+                                      MM_GENERIC_GSM_INIT_CMD);
+
     g_object_class_override_property (object_class,
                                       MM_GENERIC_GSM_PROP_POWER_UP_CMD,
                                       MM_GENERIC_GSM_POWER_UP_CMD);

plugins/mm-plugin-nokia.c

@@ -59,6 +59,22 @@ probe_result (MMPluginBase *base,
     mm_plugin_base_supports_task_complete (task, get_level_for_capabilities (capabilities));
 }
 
+static gboolean
+custom_init_response_cb (MMPluginBaseSupportsTask *task,
+                         GString *response,
+                         GError *error,
+                         guint32 tries,
+                         gboolean *out_stop,
+                         guint32 *out_level,
+                         gpointer user_data)
+{
+    if (error)
+        return tries <= 4 ? TRUE : FALSE;
+
+    /* No error, assume success */
+    return FALSE;
+}
+
 static MMPluginSupportsResult
 supports_port (MMPluginBase *base,
                MMModem *existing,
@@ -95,6 +111,12 @@ supports_port (MMPluginBase *base,
         return MM_PLUGIN_SUPPORTS_PORT_UNSUPPORTED;
     }
 
+    mm_plugin_base_supports_task_add_custom_init_command (task,
+                                                          "ATE1 E0",
+                                                          3,
+                                                          custom_init_response_cb,
+                                                          NULL);
+
     /* Otherwise kick off a probe */
     if (mm_plugin_base_probe_port (base, task, 100000, NULL))
         return MM_PLUGIN_SUPPORTS_PORT_IN_PROGRESS;