base-modem: new port getters and peekers

 * mm_base_modem_peek_port_* () will return either a port object (no new
reference), or NULL if none available.

You would usually peek() a port if you're going to use it just in the current
method, as there is no way to that reference to get invalid (we're single
threaded).

 * mm_base_modem_get_port_* () will return either NEW references to valid
port objects, or NULL if none available.

And, you would usually get() a port, whenever you want the port object to be
valid even out of the current method, for example when keeping it in the
context of an async operation.

Also, we need to consider that the primary AT port MAY BE NULL when you
peek() or get() it. This is due to the fact that we may be releasing ports
(due to device disconnection) in the middle of async operations.

13 files changed, 250 insertions, 165 deletions

diff --git a/src/mm-base-modem-at.c b/src/mm-base-modem-at.c
index 820063b8..70b4e41f 100644
--- a/src/mm-base-modem-at.c
+++ b/src/mm-base-modem-at.c
@@ -277,7 +277,7 @@ mm_base_modem_at_sequence (MMBaseModem *self,
     GError *error = NULL;
 
     /* No port given, so we'll try to guess which is best */
-    port = mm_base_modem_get_best_at_port (self, &error);
+    port = mm_base_modem_peek_best_at_port (self, &error);
     if (!port) {
         g_assert (error != NULL);
         g_simple_async_report_take_gerror_in_idle (G_OBJECT (self),
@@ -487,7 +487,7 @@ mm_base_modem_at_command (MMBaseModem *self,
     GError *error = NULL;
 
     /* No port given, so we'll try to guess which is best */
-    port = mm_base_modem_get_best_at_port (self, &error);
+    port = mm_base_modem_peek_best_at_port (self, &error);
     if (!port) {
         g_assert (error != NULL);
         g_simple_async_report_take_gerror_in_idle (G_OBJECT (self),
@@ -536,7 +536,7 @@ mm_base_modem_at_command_ignore_reply (MMBaseModem *self,
     MMAtSerialPort *port;
 
     /* No port given, so we'll try to guess which is best */
-    port = mm_base_modem_get_best_at_port (self, NULL);
+    port = mm_base_modem_peek_best_at_port (self, NULL);
     if (!port)
         /* No valid port, and we ignore replies, so just exit. */
         return;
diff --git a/src/mm-base-modem.c b/src/mm-base-modem.c
index 668199b9..74deb0ac 100644
--- a/src/mm-base-modem.c
+++ b/src/mm-base-modem.c
@@ -325,6 +325,14 @@ mm_base_modem_get_port_primary (MMBaseModem *self)
 {
     g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
 
+    return (self->priv->primary ? g_object_ref (self->priv->primary) : NULL);
+}
+
+MMAtSerialPort *
+mm_base_modem_peek_port_primary (MMBaseModem *self)
+{
+    g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
+
     return self->priv->primary;
 }
 
@@ -333,6 +341,14 @@ mm_base_modem_get_port_secondary (MMBaseModem *self)
 {
     g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
 
+    return (self->priv->secondary ? g_object_ref (self->priv->secondary) : NULL);
+}
+
+MMAtSerialPort *
+mm_base_modem_peek_port_secondary (MMBaseModem *self)
+{
+    g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
+
     return self->priv->secondary;
 }
 
@@ -341,12 +357,29 @@ mm_base_modem_get_port_qcdm (MMBaseModem *self)
 {
     g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
 
+    return (self->priv->qcdm ? g_object_ref (self->priv->qcdm) : NULL);
+}
+
+MMQcdmSerialPort *
+mm_base_modem_peek_port_qcdm (MMBaseModem *self)
+{
+    g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
+
     return self->priv->qcdm;
 }
 
 MMPort *
 mm_base_modem_get_best_data_port (MMBaseModem *self)
 {
+    MMPort *port;
+
+    port = mm_base_modem_peek_best_data_port (self);
+    return (port ? g_object_ref (port) : NULL);
+}
+
+MMPort *
+mm_base_modem_peek_best_data_port (MMBaseModem *self)
+{
     g_return_val_if_fail (MM_IS_BASE_MODEM (self), NULL);
 
     /* TODO: sometime we'll have a list of available data ports to use instead
@@ -361,24 +394,32 @@ MMAtSerialPort *
 mm_base_modem_get_best_at_port (MMBaseModem *self,
                                 GError **error)
 {
-    MMAtSerialPort *port;
+    MMAtSerialPort *best;
 
+    best = mm_base_modem_peek_best_at_port (self, error);
+    return (best ? g_object_ref (best) : NULL);
+}
+
+MMAtSerialPort *
+mm_base_modem_peek_best_at_port (MMBaseModem *self,
+                                 GError **error)
+{
     /* Decide which port to use */
-    port = mm_base_modem_get_port_primary (self);
-    if (port && !mm_port_get_connected (MM_PORT (port)))
-        return port;
+    if (self->priv->primary &&
+        !mm_port_get_connected (MM_PORT (self->priv->primary)))
+        return self->priv->primary;
 
     /* If primary port is connected, check if we can get the secondary
      * port */
-    port = mm_base_modem_get_port_secondary (self);
-    if (port && !mm_port_get_connected (MM_PORT (port)))
-        return port;
+    if (self->priv->secondary &&
+        !mm_port_get_connected (MM_PORT (self->priv->secondary)))
+        return self->priv->secondary;
 
     /* Otherwise, we cannot get any port */
     g_set_error (error,
                  MM_CORE_ERROR,
                  MM_CORE_ERROR_CONNECTED,
-                 "No port available to run command");
+                 "No AT port available to run command");
     return NULL;
 }
 
diff --git a/src/mm-base-modem.h b/src/mm-base-modem.h
index b572cf87..4318de3a 100644
--- a/src/mm-base-modem.h
+++ b/src/mm-base-modem.h
@@ -114,12 +114,20 @@ gboolean  mm_base_modem_owns_port    (MMBaseModem *self,
 gboolean  mm_base_modem_organize_ports (MMBaseModem *self,
                                         GError **error);
 
-MMAtSerialPort   *mm_base_modem_get_port_primary   (MMBaseModem *self);
-MMAtSerialPort   *mm_base_modem_get_port_secondary (MMBaseModem *self);
-MMQcdmSerialPort *mm_base_modem_get_port_qcdm      (MMBaseModem *self);
-MMPort           *mm_base_modem_get_best_data_port (MMBaseModem *self);
-MMAtSerialPort   *mm_base_modem_get_best_at_port   (MMBaseModem *self,
-                                                    GError **error);
+MMAtSerialPort   *mm_base_modem_peek_port_primary   (MMBaseModem *self);
+MMAtSerialPort   *mm_base_modem_peek_port_secondary (MMBaseModem *self);
+MMQcdmSerialPort *mm_base_modem_peek_port_qcdm      (MMBaseModem *self);
+MMAtSerialPort   *mm_base_modem_peek_best_at_port   (MMBaseModem *self,
+                                                     GError **error);
+MMPort           *mm_base_modem_peek_best_data_port (MMBaseModem *self);
+
+MMAtSerialPort   *mm_base_modem_get_port_primary    (MMBaseModem *self);
+MMAtSerialPort   *mm_base_modem_get_port_secondary  (MMBaseModem *self);
+MMQcdmSerialPort *mm_base_modem_get_port_qcdm       (MMBaseModem *self);
+MMAtSerialPort   *mm_base_modem_get_best_at_port    (MMBaseModem *self,
+                                                     GError **error);
+MMPort           *mm_base_modem_get_best_data_port  (MMBaseModem *self);
+
 
 void     mm_base_modem_set_valid    (MMBaseModem *self,
                                      gboolean valid);
diff --git a/src/mm-broadband-bearer.c b/src/mm-broadband-bearer.c
index 6201c041..64eec160 100644
--- a/src/mm-broadband-bearer.c
+++ b/src/mm-broadband-bearer.c
@@ -412,6 +412,8 @@ connect_cdma (MMBroadbandBearer *self,
 {
     DetailedConnectContext *ctx;
 
+    g_assert (primary != NULL);
+
     ctx = detailed_connect_context_new (self,
                                         modem,
                                         primary,
@@ -591,6 +593,8 @@ dial_3gpp (MMBroadbandBearer *self,
     gchar *command;
     Dial3gppContext *ctx;
 
+    g_assert (primary != NULL);
+
     ctx = dial_3gpp_context_new (self,
                                  modem,
                                  primary,
@@ -899,6 +903,8 @@ connect_3gpp (MMBroadbandBearer *self,
 {
     DetailedConnectContext *ctx;
 
+    g_assert (primary != NULL);
+
     ctx = detailed_connect_context_new (self,
                                         modem,
                                         primary,
@@ -1084,8 +1090,21 @@ connect (MMBearer *self,
                   NULL);
     g_assert (modem != NULL);
 
-    /* We will launch the ATD call in the primary port */
-    primary = mm_base_modem_get_port_primary (modem);
+    /* We will launch the ATD call in the primary port... */
+    primary = mm_base_modem_peek_port_primary (modem);
+    if (!primary) {
+        g_simple_async_report_error_in_idle (
+            G_OBJECT (self),
+            callback,
+            user_data,
+            MM_CORE_ERROR,
+            MM_CORE_ERROR_CONNECTED,
+            "Couldn't connect: couldn't get primary port");
+        g_object_unref (modem);
+        return;
+    }
+
+    /* ...only if not already connected */
     if (mm_port_get_connected (MM_PORT (primary))) {
         g_simple_async_report_error_in_idle (
             G_OBJECT (self),
@@ -1099,7 +1118,7 @@ connect (MMBearer *self,
     }
 
     /* Look for best data port, NULL if none available. */
-    data = mm_base_modem_get_best_data_port (modem);
+    data = mm_base_modem_peek_best_data_port (modem);
     if (!data) {
         g_simple_async_report_error_in_idle (
             G_OBJECT (self),
@@ -1149,7 +1168,7 @@ connect (MMBearer *self,
                 MM_BROADBAND_BEARER (self),
                 MM_BROADBAND_MODEM (modem),
                 primary,
-                mm_base_modem_get_port_secondary (modem),
+                mm_base_modem_peek_port_secondary (modem),
                 data,
                 cancellable,
                 (GAsyncReadyCallback) connect_3gpp_ready,
@@ -1170,7 +1189,7 @@ connect (MMBearer *self,
                 MM_BROADBAND_BEARER (self),
                 MM_BROADBAND_MODEM (modem),
                 primary,
-                mm_base_modem_get_port_secondary (modem),
+                mm_base_modem_peek_port_secondary (modem),
                 data,
                 cancellable,
                 (GAsyncReadyCallback) connect_cdma_ready,
@@ -1294,6 +1313,8 @@ disconnect_cdma (MMBroadbandBearer *self,
 {
     DetailedDisconnectContext *ctx;
 
+    g_assert (primary != NULL);
+
     ctx = detailed_disconnect_context_new (self,
                                            modem,
                                            primary,
@@ -1419,6 +1440,8 @@ disconnect_3gpp (MMBroadbandBearer *self,
 {
     DetailedDisconnectContext *ctx;
 
+    g_assert (primary != NULL);
+
     ctx = detailed_disconnect_context_new (self,
                                            modem,
                                            primary,
@@ -1552,6 +1575,7 @@ disconnect (MMBearer *self,
             GAsyncReadyCallback callback,
             gpointer user_data)
 {
+    MMAtSerialPort *primary;
     MMBaseModem *modem = NULL;
     DisconnectContext *ctx;
 
@@ -1571,6 +1595,20 @@ disconnect (MMBearer *self,
                   NULL);
     g_assert (modem != NULL);
 
+    /* We need the primary port to disconnect... */
+    primary = mm_base_modem_peek_port_primary (modem);
+    if (!primary) {
+        g_simple_async_report_error_in_idle (
+            G_OBJECT (self),
+            callback,
+            user_data,
+            MM_CORE_ERROR,
+            MM_CORE_ERROR_FAILED,
+            "Couldn't disconnect: couldn't get primary port");
+        g_object_unref (modem);
+        return;
+    }
+
     /* In this context, we only keep the stuff we'll need later */
     ctx = g_new0 (DisconnectContext, 1);
     ctx->self = g_object_ref (self);
@@ -1585,8 +1623,8 @@ disconnect (MMBearer *self,
             MM_BROADBAND_BEARER_GET_CLASS (self)->disconnect_3gpp (
                 MM_BROADBAND_BEARER (self),
                 MM_BROADBAND_MODEM (modem),
-                mm_base_modem_get_port_primary (modem),
-                mm_base_modem_get_port_secondary (modem),
+                primary,
+                mm_base_modem_peek_port_secondary (modem),
                 MM_BROADBAND_BEARER (self)->priv->port,
                 (GAsyncReadyCallback) disconnect_3gpp_ready,
                 ctx);
@@ -1596,8 +1634,8 @@ disconnect (MMBearer *self,
         MM_BROADBAND_BEARER_GET_CLASS (self)->disconnect_cdma (
             MM_BROADBAND_BEARER (self),
             MM_BROADBAND_MODEM (modem),
-            mm_base_modem_get_port_primary (modem),
-            mm_base_modem_get_port_secondary (modem),
+            primary,
+            mm_base_modem_peek_port_secondary (modem),
             MM_BROADBAND_BEARER (self)->priv->port,
             (GAsyncReadyCallback) disconnect_cdma_ready,
             ctx);
@@ -1655,8 +1693,11 @@ static void
 init_async_context_free (InitAsyncContext *ctx,
                          gboolean close_port)
 {
-    if (close_port)
-        mm_serial_port_close (MM_SERIAL_PORT (ctx->port));
+    if (ctx->port) {
+        if (close_port)
+            mm_serial_port_close (MM_SERIAL_PORT (ctx->port));
+        g_object_unref (ctx->port);
+    }
     g_object_unref (ctx->self);
     g_object_unref (ctx->modem);
     g_object_unref (ctx->result);
@@ -1919,6 +1960,16 @@ initable_init_async (GAsyncInitable *initable,
                   NULL);
 
     ctx->port = mm_base_modem_get_port_primary (ctx->modem);
+    if (!ctx->port) {
+        g_simple_async_result_set_error (ctx->result,
+                                         MM_CORE_ERROR,
+                                         MM_CORE_ERROR_FAILED,
+                                         "Couldn't get primary port");
+        g_simple_async_result_complete_in_idle (ctx->result);
+        init_async_context_free (ctx, FALSE);
+        return;
+    }
+
     if (!mm_serial_port_open (MM_SERIAL_PORT (ctx->port), &error)) {
         g_simple_async_result_take_error (ctx->result, error);
         g_simple_async_result_complete_in_idle (ctx->result);
diff --git a/src/mm-broadband-modem.c b/src/mm-broadband-modem.c
index 1391e437..60742d16 100644
--- a/src/mm-broadband-modem.c
+++ b/src/mm-broadband-modem.c
@@ -1246,7 +1246,6 @@ modem_load_signal_quality (MMIfaceModem *self,
                            GAsyncReadyCallback callback,
                            gpointer user_data)
 {
-    MMSerialPort *port;
     SignalQualityContext *ctx;
     GError *error = NULL;
 
@@ -1259,9 +1258,8 @@ modem_load_signal_quality (MMIfaceModem *self,
                                              modem_load_signal_quality);
 
     /* Check whether we can get a non-connected AT port */
-    port = (MMSerialPort *)mm_base_modem_get_best_at_port (MM_BASE_MODEM (self), &error);
-    if (port) {
-        ctx->port = g_object_ref (port);
+    ctx->port = (MMSerialPort *)mm_base_modem_get_best_at_port (MM_BASE_MODEM (self), &error);
+    if (ctx->port) {
         if (MM_BROADBAND_MODEM (self)->priv->modem_cind_supported)
             signal_quality_cind (ctx);
         else
@@ -1270,10 +1268,9 @@ modem_load_signal_quality (MMIfaceModem *self,
     }
 
     /* If no best AT port available (all connected), try with QCDM ports */
-    port = (MMSerialPort *)mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
-    if (port) {
+    ctx->port = (MMSerialPort *)mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
+    if (ctx->port) {
         g_error_free (error);
-        ctx->port = g_object_ref (port);
         signal_quality_qcdm (ctx);
         return;
     }
@@ -1446,13 +1443,17 @@ set_unsolicited_events_handlers (MMIfaceModem3gpp *self,
                                         set_unsolicited_events_handlers);
 
     ciev_regex = mm_3gpp_ciev_regex_get ();
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Enable unsolicited events in given port */
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         /* Set/unset unsolicited CIEV event handler */
-        mm_dbg ("%s unsolicited events handlers",
+        mm_dbg ("(%s) %s 3GPP unsolicited events handlers",
+                mm_port_get_device (MM_PORT (ports[i])),
                 enable ? "Setting" : "Removing");
         mm_at_serial_port_add_unsolicited_msg_handler (
             ports[i],
@@ -1546,10 +1547,10 @@ run_unsolicited_events_setup (UnsolicitedEventsContext *ctx)
 
     if (!ctx->cmer_primary_done) {
         ctx->cmer_primary_done = TRUE;
-        port = mm_base_modem_get_port_primary (MM_BASE_MODEM (ctx->self));
+        port = mm_base_modem_peek_port_primary (MM_BASE_MODEM (ctx->self));
     } else if (!ctx->cmer_secondary_done) {
         ctx->cmer_secondary_done = TRUE;
-        port = mm_base_modem_get_port_secondary (MM_BASE_MODEM (ctx->self));
+        port = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (ctx->self));
     }
 
     /* Enable unsolicited events in given port */
@@ -2295,31 +2296,31 @@ modem_3gpp_setup_unsolicited_registration (MMIfaceModem3gpp *self,
     MMAtSerialPort *ports[2];
     GPtrArray *array;
     guint i;
-
-    mm_dbg ("setting up unsolicited registration messages handling");
+    guint j;
 
     result = g_simple_async_result_new (G_OBJECT (self),
                                         callback,
                                         user_data,
                                         modem_3gpp_setup_unsolicited_registration);
 
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Set up CREG unsolicited message handlers in both ports */
     array = mm_3gpp_creg_regex_get (FALSE);
     for (i = 0; i < 2; i++) {
-        if (ports[i]) {
-            guint j;
-
-            for (j = 0; j < array->len; j++) {
-                mm_at_serial_port_add_unsolicited_msg_handler (
-                    MM_AT_SERIAL_PORT (ports[i]),
-                    (GRegex *) g_ptr_array_index (array, j),
-                    (MMAtSerialUnsolicitedMsgFn)registration_state_changed,
-                    self,
-                    NULL);
-            }
+        if (!ports[i])
+            continue;
+
+        mm_dbg ("(%s) setting up 3GPP unsolicited registration messages handlers",
+                mm_port_get_device (MM_PORT (ports[i])));
+        for (j = 0; j < array->len; j++) {
+            mm_at_serial_port_add_unsolicited_msg_handler (
+                MM_AT_SERIAL_PORT (ports[i]),
+                (GRegex *) g_ptr_array_index (array, j),
+                (MMAtSerialUnsolicitedMsgFn)registration_state_changed,
+                self,
+                NULL);
         }
     }
     mm_3gpp_creg_regex_destroy (array);
@@ -2349,30 +2350,32 @@ modem_3gpp_cleanup_unsolicited_registration (MMIfaceModem3gpp *self,
     MMAtSerialPort *ports[2];
     GPtrArray *array;
     guint i;
+    guint j;
 
-    mm_dbg ("cleaning up unsolicited registration messages handling");
     result = g_simple_async_result_new (G_OBJECT (self),
                                         callback,
                                         user_data,
                                         modem_3gpp_cleanup_unsolicited_registration);
 
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Set up CREG unsolicited message handlers in both ports */
     array = mm_3gpp_creg_regex_get (FALSE);
     for (i = 0; i < 2; i++) {
-        if (ports[i]) {
-            guint j;
-
-            for (j = 0; j < array->len; j++) {
-                mm_at_serial_port_add_unsolicited_msg_handler (
-                    MM_AT_SERIAL_PORT (ports[i]),
-                    (GRegex *) g_ptr_array_index (array, j),
-                    NULL,
-                    NULL,
-                    NULL);
-            }
+        if (!ports[i])
+            continue;
+
+        mm_dbg ("(%s) cleaning up unsolicited registration messages handlers",
+                mm_port_get_device (MM_PORT (ports[i])));
+
+        for (j = 0; j < array->len; j++) {
+            mm_at_serial_port_add_unsolicited_msg_handler (
+                MM_AT_SERIAL_PORT (ports[i]),
+                (GRegex *) g_ptr_array_index (array, j),
+                NULL,
+                NULL,
+                NULL);
         }
     }
     mm_3gpp_creg_regex_destroy (array);
@@ -2858,7 +2861,7 @@ cleanup_registration_sequence_ready (MMBroadbandModem *self,
     if (!ctx->secondary_done) {
         MMAtSerialPort *secondary;
 
-        secondary = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+        secondary = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
         if (secondary) {
             /* Now use the same registration setup in secondary port, if any */
             ctx->secondary_done = TRUE;
@@ -2911,7 +2914,7 @@ modem_3gpp_cleanup_cs_registration (MMIfaceModem3gpp *self,
 
     mm_base_modem_at_command_in_port (
         MM_BASE_MODEM (self),
-        mm_base_modem_get_port_primary (MM_BASE_MODEM (self)),
+        mm_base_modem_peek_port_primary (MM_BASE_MODEM (self)),
         ctx->command,
         10,
         FALSE,
@@ -2936,7 +2939,7 @@ modem_3gpp_cleanup_ps_registration (MMIfaceModem3gpp *self,
 
     mm_base_modem_at_command_in_port (
         MM_BASE_MODEM (self),
-        mm_base_modem_get_port_primary (MM_BASE_MODEM (self)),
+        mm_base_modem_peek_port_primary (MM_BASE_MODEM (self)),
         ctx->command,
         10,
         FALSE,
@@ -3040,13 +3043,13 @@ setup_registration_sequence_ready (MMBroadbandModem *self,
             return;
         }
 
-        secondary = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+        secondary = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
         if (secondary) {
             /* Now use the same registration setup in secondary port, if any */
             ctx->secondary_done = TRUE;
             mm_base_modem_at_command_in_port (
                 MM_BASE_MODEM (self),
-                mm_base_modem_get_port_primary (MM_BASE_MODEM (self)),
+                mm_base_modem_peek_port_primary (MM_BASE_MODEM (self)),
                 g_variant_get_string (command, NULL),
                 3,
                 FALSE,
@@ -3078,7 +3081,7 @@ modem_3gpp_setup_cs_registration (MMIfaceModem3gpp *self,
                                              modem_3gpp_setup_cs_registration);
     mm_base_modem_at_sequence_in_port (
         MM_BASE_MODEM (self),
-        mm_base_modem_get_port_primary (MM_BASE_MODEM (self)),
+        mm_base_modem_peek_port_primary (MM_BASE_MODEM (self)),
         cs_registration_sequence,
         NULL,  /* response processor context */
         NULL,  /* response processor context free */
@@ -3101,7 +3104,7 @@ modem_3gpp_setup_ps_registration (MMIfaceModem3gpp *self,
                                              modem_3gpp_setup_ps_registration);
     mm_base_modem_at_sequence_in_port (
         MM_BASE_MODEM (self),
-        mm_base_modem_get_port_primary (MM_BASE_MODEM (self)),
+        mm_base_modem_peek_port_primary (MM_BASE_MODEM (self)),
         ps_registration_sequence,
         NULL,  /* response processor context */
         NULL,  /* response processor context free */
@@ -3501,13 +3504,16 @@ set_unsolicited_result_code_handlers (MMIfaceModem3gppUssd *self,
                                         set_unsolicited_events_handlers);
 
     cusd_regex = mm_3gpp_cusd_regex_get ();
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Enable unsolicited result codes in given port */
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
         /* Set/unset unsolicited CUSD event handler */
-        mm_dbg ("%s unsolicited result code handlers",
+        mm_dbg ("(%s) %s unsolicited result code handlers",
+                mm_port_get_device (MM_PORT (ports[i])),
                 enable ? "Setting" : "Removing");
         mm_at_serial_port_add_unsolicited_msg_handler (
             ports[i],
@@ -4150,13 +4156,17 @@ set_messaging_unsolicited_events_handlers (MMIfaceModemMessaging *self,
                                         set_messaging_unsolicited_events_handlers);
 
     cmti_regex = mm_3gpp_cmti_regex_get ();
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Enable unsolicited events in given port */
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         /* Set/unset unsolicited CMTI event handler */
-        mm_dbg ("%s messaging unsolicited events handlers",
+        mm_dbg ("(%s) %s messaging unsolicited events handlers",
+                mm_port_get_device (MM_PORT (ports[i])),
                 enable ? "Setting" : "Removing");
         mm_at_serial_port_add_unsolicited_msg_handler (
             ports[i],
@@ -4679,7 +4689,7 @@ modem_cdma_get_hdr_state (MMIfaceModemCdma *self,
     HdrStateContext *ctx;
     GByteArray *hdrstate;
 
-    qcdm = mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
+    qcdm = mm_base_modem_peek_port_qcdm (MM_BASE_MODEM (self));
     if (!qcdm) {
         g_simple_async_report_error_in_idle (G_OBJECT (self),
                                              callback,
@@ -4803,7 +4813,7 @@ modem_cdma_get_call_manager_state (MMIfaceModemCdma *self,
     CallManagerStateContext *ctx;
     GByteArray *cmstate;
 
-    qcdm = mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
+    qcdm = mm_base_modem_peek_port_qcdm (MM_BASE_MODEM (self));
     if (!qcdm) {
         g_simple_async_report_error_in_idle (G_OBJECT (self),
                                              callback,
@@ -5093,8 +5103,6 @@ modem_cdma_get_cdma1x_serving_system (MMIfaceModemCdma *self,
     if (ctx->qcdm) {
         GByteArray *cdma_status;
 
-        g_object_ref (ctx->qcdm);
-
         /* Setup command */
         cdma_status = g_byte_array_sized_new (25);
         cdma_status->len = qcdm_cmd_cdma_status_new ((char *) cdma_status->data, 25);
@@ -5351,7 +5359,7 @@ modem_cdma_get_detailed_registration_state (MMIfaceModemCdma *self,
     /* The default implementation to get detailed registration state
      * requires the use of an AT port; so if we cannot get any, just
      * return the error */
-    port = mm_base_modem_get_best_at_port (MM_BASE_MODEM (self), &error);
+    port = mm_base_modem_peek_best_at_port (MM_BASE_MODEM (self), &error);
     if (!port) {
         g_simple_async_report_take_gerror_in_idle (G_OBJECT (self),
                                                    callback,
@@ -5534,7 +5542,7 @@ modem_cdma_setup_registration_checks (MMIfaceModemCdma *self,
                                              modem_cdma_setup_registration_checks);
 
     /* Check if we have a QCDM port */
-    ctx->has_qcdm_port = !!mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
+    ctx->has_qcdm_port = !!mm_base_modem_peek_port_qcdm (MM_BASE_MODEM (self));
 
     /* If we have cached results of Sprint command checking, use them */
     if (ctx->self->priv->checked_sprint_support) {
@@ -5771,14 +5779,17 @@ setup_ports (MMBroadbandModem *self)
     GPtrArray *array;
     gint i, j;
 
-    ports[0] = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
-    ports[1] = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
+    ports[0] = mm_base_modem_peek_port_primary (MM_BASE_MODEM (self));
+    ports[1] = mm_base_modem_peek_port_secondary (MM_BASE_MODEM (self));
 
     /* Cleanup all unsolicited message handlers in all AT ports */
 
     /* Set up CREG unsolicited message handlers, with NULL callbacks */
     array = mm_3gpp_creg_regex_get (FALSE);
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         for (j = 0; j < array->len; j++) {
             mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (ports[i]),
                                                            (GRegex *)g_ptr_array_index (array, j),
@@ -5791,7 +5802,10 @@ setup_ports (MMBroadbandModem *self)
 
     /* Set up CIEV unsolicited message handler, with NULL callback */
     regex = mm_3gpp_ciev_regex_get ();
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (ports[i]),
                                                        regex,
                                                        NULL,
@@ -5802,7 +5816,10 @@ setup_ports (MMBroadbandModem *self)
 
     /* Set up CMTI unsolicited message handler, with NULL callback */
     regex = mm_3gpp_cmti_regex_get ();
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (ports[i]),
                                                        regex,
                                                        NULL,
@@ -5813,7 +5830,10 @@ setup_ports (MMBroadbandModem *self)
 
     /* Set up CUSD unsolicited message handler, with NULL callback */
     regex = mm_3gpp_cusd_regex_get ();
-    for (i = 0; ports[i] && i < 2; i++) {
+    for (i = 0; i < 2; i++) {
+        if (!ports[i])
+            continue;
+
         mm_at_serial_port_add_unsolicited_msg_handler (MM_AT_SERIAL_PORT (ports[i]),
                                                        regex,
                                                        NULL,
@@ -6396,9 +6416,11 @@ initialize_context_complete_and_free (InitializeContext *ctx)
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->result);
     /* balance open/close count */
-    if (ctx->close_port)
-        mm_serial_port_close (MM_SERIAL_PORT (ctx->port));
-    g_object_unref (ctx->port);
+    if (ctx->port) {
+        if (ctx->close_port)
+            mm_serial_port_close (MM_SERIAL_PORT (ctx->port));
+        g_object_unref (ctx->port);
+    }
     g_object_unref (ctx->self);
     g_free (ctx);
 }
@@ -6473,11 +6495,20 @@ initialize_step (InitializeContext *ctx)
     case INITIALIZE_STEP_PRIMARY_OPEN: {
         GError *error = NULL;
 
+        ctx->port = mm_base_modem_get_port_primary (MM_BASE_MODEM (ctx->self));
+        if (!ctx->port) {
+            g_simple_async_result_set_error (ctx->result,
+                                             MM_CORE_ERROR,
+                                             MM_CORE_ERROR_FAILED,
+                                             "Cannot initialize: couldn't get primary port");
+            initialize_context_complete_and_free (ctx);
+            return;
+        }
+
         /* Open and send first commands to the primary serial port.
          * We do keep the primary port open during the whole initialization
          * sequence. Note that this port is not really passed to the interfaces,
          * they will get the primary port themselves. */
-        ctx->port = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (ctx->self)));
         if (!mm_serial_port_open (MM_SERIAL_PORT (ctx->port), &error)) {
             g_simple_async_result_take_error (ctx->result, error);
             initialize_context_complete_and_free (ctx);
diff --git a/src/mm-iface-modem-3gpp-ussd.c b/src/mm-iface-modem-3gpp-ussd.c
index 4e6b47f4..fd902142 100644
--- a/src/mm-iface-modem-3gpp-ussd.c
+++ b/src/mm-iface-modem-3gpp-ussd.c
@@ -405,7 +405,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModem3gppUssd *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModem3gppUssd *skeleton;
@@ -420,7 +419,6 @@ disabling_context_new (MMIfaceModem3gppUssd *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -439,7 +437,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -551,7 +548,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModem3gppUssd *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModem3gppUssd *skeleton;
@@ -566,7 +562,6 @@ enabling_context_new (MMIfaceModem3gppUssd *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -585,7 +580,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem-3gpp.c b/src/mm-iface-modem-3gpp.c
index 03a86967..78cf94d3 100644
--- a/src/mm-iface-modem-3gpp.c
+++ b/src/mm-iface-modem-3gpp.c
@@ -925,7 +925,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModem3gpp *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModem *skeleton;
@@ -940,7 +939,6 @@ disabling_context_new (MMIfaceModem3gpp *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -959,7 +957,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -1148,7 +1145,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModem3gpp *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModem3gpp *skeleton;
@@ -1163,7 +1159,6 @@ enabling_context_new (MMIfaceModem3gpp *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -1182,7 +1177,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem-cdma.c b/src/mm-iface-modem-cdma.c
index c5983ddf..ec5d27e6 100644
--- a/src/mm-iface-modem-cdma.c
+++ b/src/mm-iface-modem-cdma.c
@@ -1101,7 +1101,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModemCdma *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemCdma *skeleton;
@@ -1116,7 +1115,6 @@ disabling_context_new (MMIfaceModemCdma *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -1135,7 +1133,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -1196,7 +1193,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModemCdma *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemCdma *skeleton;
@@ -1211,7 +1207,6 @@ enabling_context_new (MMIfaceModemCdma *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -1230,7 +1225,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem-location.c b/src/mm-iface-modem-location.c
index a021a563..09933375 100644
--- a/src/mm-iface-modem-location.c
+++ b/src/mm-iface-modem-location.c
@@ -451,7 +451,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModemLocation *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemLocation *skeleton;
@@ -466,7 +465,6 @@ disabling_context_new (MMIfaceModemLocation *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -485,7 +483,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -575,7 +572,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModemLocation *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemLocation *skeleton;
@@ -590,7 +586,6 @@ enabling_context_new (MMIfaceModemLocation *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -609,7 +604,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem-messaging.c b/src/mm-iface-modem-messaging.c
index 2545cdc0..cf9f0d34 100644
--- a/src/mm-iface-modem-messaging.c
+++ b/src/mm-iface-modem-messaging.c
@@ -486,7 +486,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModemMessaging *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemMessaging *skeleton;
@@ -501,7 +500,6 @@ disabling_context_new (MMIfaceModemMessaging *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -520,7 +518,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -648,7 +645,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModemMessaging *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemMessaging *skeleton;
@@ -665,7 +661,6 @@ enabling_context_new (MMIfaceModemMessaging *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -684,7 +679,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem-time.c b/src/mm-iface-modem-time.c
index 2502ceca..70f3ed05 100644
--- a/src/mm-iface-modem-time.c
+++ b/src/mm-iface-modem-time.c
@@ -395,7 +395,6 @@ typedef enum {
 
 struct _DisablingContext {
     MMIfaceModemTime *self;
-    MMAtSerialPort *primary;
     DisablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemTime *skeleton;
@@ -410,7 +409,6 @@ disabling_context_new (MMIfaceModemTime *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -429,7 +427,6 @@ disabling_context_complete_and_free (DisablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
@@ -570,7 +567,6 @@ typedef enum {
 
 struct _EnablingContext {
     MMIfaceModemTime *self;
-    MMAtSerialPort *primary;
     EnablingStep step;
     GSimpleAsyncResult *result;
     MmGdbusModemTime *skeleton;
@@ -585,7 +581,6 @@ enabling_context_new (MMIfaceModemTime *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -604,7 +599,6 @@ enabling_context_complete_and_free (EnablingContext *ctx)
 {
     g_simple_async_result_complete_in_idle (ctx->result);
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
     g_object_unref (ctx->result);
     g_object_unref (ctx->skeleton);
     g_free (ctx);
diff --git a/src/mm-iface-modem.c b/src/mm-iface-modem.c
index 32f66a7a..0e3b0017 100644
--- a/src/mm-iface-modem.c
+++ b/src/mm-iface-modem.c
@@ -2300,13 +2300,9 @@ disabling_context_new (MMIfaceModem *self,
 
     ctx = g_new0 (DisablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
+    ctx->primary = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
     ctx->secondary = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
-    if (ctx->secondary)
-        g_object_ref (ctx->secondary);
     ctx->qcdm = mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
-    if (ctx->qcdm)
-        g_object_ref (ctx->qcdm);
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -2341,7 +2337,8 @@ disabling_context_complete_and_free (DisablingContext *ctx)
                                      MM_MODEM_STATE_CHANGE_REASON_UNKNOWN);
 
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
+    if (ctx->primary)
+        g_object_unref (ctx->primary);
     if (ctx->secondary)
         g_object_unref (ctx->secondary);
     if (ctx->qcdm)
@@ -2427,7 +2424,7 @@ interface_disabling_step (DisablingContext *ctx)
          * be safe to check whether they are really open before trying to close.
          */
         mm_dbg ("Closing all ports...");
-        if (mm_serial_port_is_open (MM_SERIAL_PORT (ctx->primary)))
+        if (ctx->primary && mm_serial_port_is_open (MM_SERIAL_PORT (ctx->primary)))
             mm_serial_port_close (MM_SERIAL_PORT (ctx->primary));
         if (ctx->secondary && mm_serial_port_is_open (MM_SERIAL_PORT (ctx->secondary)))
             mm_serial_port_close (MM_SERIAL_PORT (ctx->secondary));
@@ -2503,13 +2500,9 @@ enabling_context_new (MMIfaceModem *self,
 
     ctx = g_new0 (EnablingContext, 1);
     ctx->self = g_object_ref (self);
-    ctx->primary = g_object_ref (mm_base_modem_get_port_primary (MM_BASE_MODEM (self)));
+    ctx->primary = mm_base_modem_get_port_primary (MM_BASE_MODEM (self));
     ctx->secondary = mm_base_modem_get_port_secondary (MM_BASE_MODEM (self));
-    if (ctx->secondary)
-        g_object_ref (ctx->secondary);
     ctx->qcdm = mm_base_modem_get_port_qcdm (MM_BASE_MODEM (self));
-    if (ctx->qcdm)
-        g_object_ref (ctx->qcdm);
     ctx->result = g_simple_async_result_new (G_OBJECT (self),
                                              callback,
                                              user_data,
@@ -2554,7 +2547,8 @@ enabling_context_complete_and_free (EnablingContext *ctx)
     }
 
     g_object_unref (ctx->self);
-    g_object_unref (ctx->primary);
+    if (ctx->primary)
+        g_object_unref (ctx->primary);
     if (ctx->secondary)
         g_object_unref (ctx->secondary);
     if (ctx->qcdm)
@@ -2737,6 +2731,15 @@ interface_enabling_step (EnablingContext *ctx)
         GError *error = NULL;
 
         /* Open primary port */
+        if (!ctx->primary) {
+            g_simple_async_result_set_error (ctx->result,
+                                             MM_CORE_ERROR,
+                                             MM_CORE_ERROR_FAILED,
+                                             "Cannot enable: no primary port");
+            enabling_context_complete_and_free (ctx);
+            return;
+        }
+
         if (!mm_serial_port_open (MM_SERIAL_PORT (ctx->primary), &error)) {
             g_simple_async_result_take_error (ctx->result, error);
             enabling_context_complete_and_free (ctx);
diff --git a/src/mm-sim.c b/src/mm-sim.c
index 95a1eec5..fbb20752 100644
--- a/src/mm-sim.c
+++ b/src/mm-sim.c
@@ -1386,15 +1386,11 @@ struct _InitAsyncContext {
     MMSim *self;
     InitializationStep step;
     guint sim_identifier_tries;
-    MMAtSerialPort *port;
 };
 
 static void
-init_async_context_free (InitAsyncContext *ctx,
-                         gboolean close_port)
+init_async_context_free (InitAsyncContext *ctx)
 {
-    if (close_port)
-        mm_serial_port_close (MM_SERIAL_PORT (ctx->port));
     g_object_unref (ctx->self);
     g_object_unref (ctx->result);
     if (ctx->cancellable)
@@ -1569,7 +1565,7 @@ interface_initialization_step (InitAsyncContext *ctx)
         /* We are done without errors! */
         g_simple_async_result_set_op_res_gboolean (ctx->result, TRUE);
         g_simple_async_result_complete_in_idle (ctx->result);
-        init_async_context_free (ctx, TRUE);
+        init_async_context_free (ctx);
         return;
     }
 
@@ -1585,7 +1581,6 @@ common_init_async (GAsyncInitable *initable,
 
 {
     InitAsyncContext *ctx;
-    GError *error = NULL;
 
     ctx = g_new (InitAsyncContext, 1);
     ctx->self = g_object_ref (initable);
@@ -1599,14 +1594,6 @@ common_init_async (GAsyncInitable *initable,
     ctx->step = INITIALIZATION_STEP_FIRST;
     ctx->sim_identifier_tries = 0;
 
-    ctx->port = mm_base_modem_get_port_primary (ctx->self->priv->modem);
-    if (!mm_serial_port_open (MM_SERIAL_PORT (ctx->port), &error)) {
-        g_simple_async_result_take_error (ctx->result, error);
-        g_simple_async_result_complete_in_idle (ctx->result);
-        init_async_context_free (ctx, FALSE);
-        return;
-    }
-
     interface_initialization_step (ctx);
 }