iface-location: allow enabling without SIM

When the modem is in a failed state because of a SIM-related error,
like a missing SIM, or if the modem is SIM-locked, allow the
Location interface to initialize and be enabled anyway.

This allows someone without a SIM to use the GPS, which does not
particularly require a phone subscription. It also allows
someone with a SIM to use the GPS even if the SIM is still
locked.

This patch was reworked, while keeping the original idea, by:
Aleksander Morgado <aleksander@aleksander.es>

Fixes #183

cli/mmcli-modem-location.c

@@ -254,11 +254,6 @@ context_free (void)
 static void
 ensure_modem_location (void)
 {
-    if (mm_modem_get_state (mm_object_peek_modem (ctx->object)) < MM_MODEM_STATE_ENABLED) {
-        g_printerr ("error: modem not enabled yet\n");
-        exit (EXIT_FAILURE);
-    }
-
     if (!ctx->modem_location) {
         g_printerr ("error: modem has no location capabilities\n");
         exit (EXIT_FAILURE);

include/ModemManager-enums.h

@@ -1113,8 +1113,13 @@ typedef enum { /*< underscore_name=mm_sms_cdma_service_category >*/
  * @MM_MODEM_LOCATION_SOURCE_GPS_NMEA: GPS location given as NMEA traces.
  * @MM_MODEM_LOCATION_SOURCE_CDMA_BS: CDMA base station position.
  * @MM_MODEM_LOCATION_SOURCE_GPS_UNMANAGED: No location given, just GPS module setup. Since 1.4.
- * @MM_MODEM_LOCATION_SOURCE_AGPS_MSA: Mobile Station Assisted A-GPS location requested. Since 1.12.
+ * @MM_MODEM_LOCATION_SOURCE_AGPS_MSA: Mobile Station Assisted A-GPS location requested. In
- * @MM_MODEM_LOCATION_SOURCE_AGPS_MSB: Mobile Station Based A-GPS location requested. Since 1.12.
+ *  MSA A-GPS, the position fix is computed by a server online. The modem must have a valid SIM
+ *  card inserted and be enabled for this mode to be allowed. Since 1.12.
+ * @MM_MODEM_LOCATION_SOURCE_AGPS_MSB: Mobile Station Based A-GPS location requested. In MSB
+ *  A-GPS, the position fix is computed by the modem, but it first gathers information  from an
+ *  online server to facilitate the process (e.g. ephemeris). The modem must have a valid SIM
+ *  card inserted and be enabled for this mode to be allowed. Since 1.12.
  *
  * Sources of location information supported by the modem.
  *

introspection/org.freedesktop.ModemManager1.Modem.Location.xml

@@ -40,18 +40,14 @@
         no GPS sources are requested by the user, the GNSS engine will need
         to be stopped explicitly).
 
-        This method may require the client to authenticate itself.
-
         When location signaling is enabled by the user, any client application (including
         malicious ones!) would be able to use the #org.freedesktop.ModemManager1.Modem.Location:Location
         property to receive location updates. If further security is desired, the
         @signal_location argument can be set to %FALSE to disable location
         updates via D-Bus signals and require applications to call
         authenticated APIs (like <link linkend="gdbus-method-org-freedesktop-ModemManager1-Modem-Location.GetLocation">GetLocation()</link>)
-        to get the location information.
+        to get the location information. By default location signaling is disabled,
-
+        and therefore the #org.freedesktop.ModemManager1.Modem.Location:Location property will not
-        By default location signaling is disabled, and therefore the
-        #org.freedesktop.ModemManager1.Modem.Location:Location property will not
         be usable until explicitly enabled by the user.
 
         The optional
@@ -62,12 +58,12 @@
         <link linkend="MM-MODEM-LOCATION-SOURCE-GPS-RAW:CAPS">MM_MODEM_LOCATION_SOURCE_GPS_RAW</link>
         or
         <link linkend="MM-MODEM-LOCATION-SOURCE-GPS-NMEA:CAPS">MM_MODEM_LOCATION_SOURCE_GPS_NMEA</link>.
+        Both A-GPS operation modes rely on having a valid data connection to connect to an online
+        server, and therefore require the modem to have a valid SIM card and be enabled. If no A-GPS mode
+        is specified, standalone GPS is assumed.
 
-        Both
+        Since 1.24, standalone GPS sources may be enabled even with the modem in failed state, e.g.
-        <link linkend="MM-MODEM-LOCATION-SOURCE-AGPS-MSA:CAPS">MM_MODEM_LOCATION_SOURCE_AGPS_MSA</link>
+        when there is no SIM card inserted.
-        and
-        <link linkend="MM-MODEM-LOCATION-SOURCE-AGPS-MSB:CAPS">MM_MODEM_LOCATION_SOURCE_AGPS_MSB</link>
-        cannot be given at the same time, and if none given, standalone GPS is assumed.
 
         Since: 1.0
     -->
@@ -119,9 +115,10 @@
         There is no maximum @data size limit specified, default DBus system bus limits apply.
 
         This method may be used when the device does not have a mobile network connection by
-        itself, and therefore it cannot use any A-GPS server to improve the accuracy of the
+        itself (e.g. when not even a SIM is inserted), and therefore it cannot use any A-GPS
-        position. In this case, the user can instead download the assistance data files using
+        server to improve the accuracy of the position. In this case, the user can instead
-        a WiFi or LAN network, and inject them to the GNSS engine manually.
+        download the assistance data files using a WiFi or LAN network, and inject them to
+        the GNSS engine manually.
 
         Since: 1.10
     -->

src/mm-broadband-modem.c

@@ -12339,13 +12339,13 @@ typedef enum {
     INITIALIZE_STEP_IFACE_3GPP_PROFILE_MANAGER,
     INITIALIZE_STEP_IFACE_3GPP_USSD,
     INITIALIZE_STEP_IFACE_CDMA,
-    INITIALIZE_STEP_IFACE_LOCATION,
     INITIALIZE_STEP_IFACE_MESSAGING,
     INITIALIZE_STEP_IFACE_TIME,
     INITIALIZE_STEP_IFACE_SIGNAL,
     INITIALIZE_STEP_IFACE_OMA,
     INITIALIZE_STEP_IFACE_SAR,
     INITIALIZE_STEP_FALLBACK_LIMITED,
+    INITIALIZE_STEP_IFACE_LOCATION,
     INITIALIZE_STEP_IFACE_VOICE,
     INITIALIZE_STEP_IFACE_FIRMWARE,
     INITIALIZE_STEP_IFACE_SIMPLE,
@@ -12637,14 +12637,6 @@ initialize_step (GTask *task)
         ctx->step++;
        /* fall through */
 
-    case INITIALIZE_STEP_IFACE_LOCATION:
-        /* Initialize the Location interface */
-        mm_iface_modem_location_initialize (MM_IFACE_MODEM_LOCATION (ctx->self),
-                                            g_task_get_cancellable (task),
-                                            (GAsyncReadyCallback)iface_modem_location_initialize_ready,
-                                            task);
-        return;
-
     case INITIALIZE_STEP_IFACE_MESSAGING:
         /* Initialize the Messaging interface */
         mm_iface_modem_messaging_initialize (MM_IFACE_MODEM_MESSAGING (ctx->self),
@@ -12691,6 +12683,14 @@ initialize_step (GTask *task)
         ctx->step++;
        /* fall through */
 
+    case INITIALIZE_STEP_IFACE_LOCATION:
+        /* Initialize the Location interface */
+        mm_iface_modem_location_initialize (MM_IFACE_MODEM_LOCATION (ctx->self),
+                                            g_task_get_cancellable (task),
+                                            (GAsyncReadyCallback)iface_modem_location_initialize_ready,
+                                            task);
+        return;
+
     case INITIALIZE_STEP_IFACE_VOICE:
         /* Initialize the Voice interface */
         mm_iface_modem_voice_initialize (MM_IFACE_MODEM_VOICE (ctx->self),
@@ -12731,16 +12731,16 @@ initialize_step (GTask *task)
                                      "Modem in failed state: %s",
                                      mm_modem_state_failed_reason_get_string (reason));
 
-                /* Ensure we only leave the Modem, Voice and Firmware interfaces
+                /* Ensure we only leave the Modem, Voice, Location and Firmware interfaces
                  * around. A failure could be caused by firmware issues, which
                  * a firmware update, switch, or provisioning could fix. We also
                  * leave the Voice interface around so that we can attempt
-                 * emergency voice calls.
+                 * emergency voice calls, and the Location interface so that we can use
+                 * GNSS without a SIM card
                  */
                 mm_iface_modem_3gpp_profile_manager_shutdown (MM_IFACE_MODEM_3GPP_PROFILE_MANAGER (ctx->self));
                 mm_iface_modem_3gpp_ussd_shutdown (MM_IFACE_MODEM_3GPP_USSD (ctx->self));
                 mm_iface_modem_cdma_shutdown (MM_IFACE_MODEM_CDMA (ctx->self));
-                mm_iface_modem_location_shutdown (MM_IFACE_MODEM_LOCATION (ctx->self));
                 mm_iface_modem_signal_shutdown (MM_IFACE_MODEM_SIGNAL (ctx->self));
                 mm_iface_modem_messaging_shutdown (MM_IFACE_MODEM_MESSAGING (ctx->self));
                 mm_iface_modem_time_shutdown (MM_IFACE_MODEM_TIME (ctx->self));

src/mm-iface-modem-location.c

@@ -890,11 +890,11 @@ setup_gathering (MMIfaceModemLocation *self,
 /*****************************************************************************/
 
 typedef struct {
-    MmGdbusModemLocation *skeleton;
+    MmGdbusModemLocation  *skeleton;
     GDBusMethodInvocation *invocation;
-    MMIfaceModemLocation *self;
+    MMIfaceModemLocation  *self;
-    guint32 sources;
+    guint32                sources;
-    gboolean signal_location;
+    gboolean               signal_location;
 } HandleSetupContext;
 
 static void
@@ -903,13 +903,13 @@ handle_setup_context_free (HandleSetupContext *ctx)
     g_object_unref (ctx->skeleton);
     g_object_unref (ctx->invocation);
     g_object_unref (ctx->self);
-    g_free (ctx);
+    g_slice_free (HandleSetupContext, ctx);
 }
 
 static void
 setup_gathering_ready (MMIfaceModemLocation *self,
-                       GAsyncResult *res,
+                       GAsyncResult         *res,
-                       HandleSetupContext *ctx)
+                       HandleSetupContext   *ctx)
 {
     GError *error = NULL;
 
@@ -922,15 +922,16 @@ setup_gathering_ready (MMIfaceModemLocation *self,
 }
 
 static void
-handle_setup_auth_ready (MMBaseModem *self,
+handle_setup_auth_ready (MMBaseModem        *self,
-                         GAsyncResult *res,
+                         GAsyncResult       *res,
                          HandleSetupContext *ctx)
 {
-    GError *error = NULL;
+    GError                *error = NULL;
-    MMModemState modem_state;
+    MMModemState           modem_state;
-    MMModemLocationSource not_supported;
+    MMModemLocationSource  not_supported;
-    LocationContext *location_ctx;
+    MMModemLocationSource  require_enabled;
-    gchar *str;
+    LocationContext       *location_ctx;
+    g_autofree gchar      *str = NULL;
 
     if (!mm_base_modem_authorize_finish (self, res, &error)) {
         mm_dbus_method_invocation_take_error (ctx->invocation, error);
@@ -938,17 +939,6 @@ handle_setup_auth_ready (MMBaseModem *self,
         return;
     }
 
-    modem_state = MM_MODEM_STATE_UNKNOWN;
-    g_object_get (self,
-                  MM_IFACE_MODEM_STATE, &modem_state,
-                  NULL);
-    if (modem_state < MM_MODEM_STATE_ENABLED) {
-        mm_dbus_method_invocation_return_error_literal (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_WRONG_STATE,
-                                                        "Cannot setup location: device not yet enabled");
-        handle_setup_context_free (ctx);
-        return;
-    }
-
     /* If any of the location sources being enabled is NOT supported, set error */
     not_supported = ((mm_gdbus_modem_location_get_capabilities (ctx->skeleton) ^ ctx->sources) & ctx->sources);
     if (not_supported != MM_MODEM_LOCATION_SOURCE_NONE) {
@@ -956,7 +946,26 @@ handle_setup_auth_ready (MMBaseModem *self,
         mm_dbus_method_invocation_return_error (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_UNSUPPORTED,
                                                "Cannot enable unsupported location sources: '%s'", str);
         handle_setup_context_free (ctx);
-        g_free (str);
+        return;
+    }
+
+    modem_state = MM_MODEM_STATE_UNKNOWN;
+    g_object_get (self,
+                  MM_IFACE_MODEM_STATE, &modem_state,
+                  NULL);
+
+    /* Location sources that require any kind of network access may be
+     * enabled only when the modem is enabled. Generic standalone GPS may be
+     * enabled even without a SIM card */
+    require_enabled = ctx->sources & (MM_MODEM_LOCATION_SOURCE_3GPP_LAC_CI |
+                                      MM_MODEM_LOCATION_SOURCE_CDMA_BS |
+                                      MM_MODEM_LOCATION_SOURCE_AGPS_MSA |
+                                      MM_MODEM_LOCATION_SOURCE_AGPS_MSB);
+    if (require_enabled && (modem_state < MM_MODEM_STATE_ENABLED)) {
+        str = mm_modem_location_source_build_string_from_mask (require_enabled);
+        mm_dbus_method_invocation_return_error (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_WRONG_STATE,
+                                                "Cannot enable location '%s': device not yet enabled", str);
+        handle_setup_context_free (ctx);
         return;
     }
 
@@ -983,7 +992,6 @@ handle_setup_auth_ready (MMBaseModem *self,
 
     str = mm_modem_location_source_build_string_from_mask (ctx->sources);
     mm_obj_dbg (self, "setting up location sources: '%s'", str);
-    g_free (str);
 
     /* Go on to enable or disable the requested sources */
     setup_gathering (ctx->self,
@@ -993,15 +1001,15 @@ handle_setup_auth_ready (MMBaseModem *self,
 }
 
 static gboolean
-handle_setup (MmGdbusModemLocation *skeleton,
+handle_setup (MmGdbusModemLocation  *skeleton,
               GDBusMethodInvocation *invocation,
-              guint32 sources,
+              guint32                sources,
-              gboolean signal_location,
+              gboolean               signal_location,
-              MMIfaceModemLocation *self)
+              MMIfaceModemLocation  *self)
 {
     HandleSetupContext *ctx;
 
-    ctx = g_new (HandleSetupContext, 1);
+    ctx = g_slice_new0 (HandleSetupContext);
     ctx->skeleton = g_object_ref (skeleton);
     ctx->invocation = g_object_ref (invocation);
     ctx->self = g_object_ref (self);
@@ -1019,10 +1027,10 @@ handle_setup (MmGdbusModemLocation *skeleton,
 /*****************************************************************************/
 
 typedef struct {
-    MmGdbusModemLocation *skeleton;
+    MmGdbusModemLocation  *skeleton;
     GDBusMethodInvocation *invocation;
-    MMIfaceModemLocation *self;
+    MMIfaceModemLocation  *self;
-    gchar *supl;
+    gchar                 *supl;
 } HandleSetSuplServerContext;
 
 static void
@@ -1036,8 +1044,8 @@ handle_set_supl_server_context_free (HandleSetSuplServerContext *ctx)
 }
 
 static void
-set_supl_server_ready (MMIfaceModemLocation *self,
+set_supl_server_ready (MMIfaceModemLocation       *self,
-                       GAsyncResult *res,
+                       GAsyncResult               *res,
                        HandleSetSuplServerContext *ctx)
 {
     GError *error = NULL;
@@ -1053,12 +1061,11 @@ set_supl_server_ready (MMIfaceModemLocation *self,
 }
 
 static void
-handle_set_supl_server_auth_ready (MMBaseModem *self,
+handle_set_supl_server_auth_ready (MMBaseModem                *self,
-                                   GAsyncResult *res,
+                                   GAsyncResult               *res,
                                    HandleSetSuplServerContext *ctx)
 {
     GError *error = NULL;
-    MMModemState modem_state;
 
     if (!mm_base_modem_authorize_finish (self, res, &error)) {
         mm_dbus_method_invocation_take_error (ctx->invocation, error);
@@ -1066,17 +1073,6 @@ handle_set_supl_server_auth_ready (MMBaseModem *self,
         return;
     }
 
-    modem_state = MM_MODEM_STATE_UNKNOWN;
-    g_object_get (self,
-                  MM_IFACE_MODEM_STATE, &modem_state,
-                  NULL);
-    if (modem_state < MM_MODEM_STATE_ENABLED) {
-        mm_dbus_method_invocation_return_error_literal (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_WRONG_STATE,
-                                                        "Cannot set SUPL server: device not yet enabled");
-        handle_set_supl_server_context_free (ctx);
-        return;
-    }
-
     /* If A-GPS is NOT supported, set error */
     if (!(mm_gdbus_modem_location_get_capabilities (ctx->skeleton) & (MM_MODEM_LOCATION_SOURCE_AGPS_MSA | MM_MODEM_LOCATION_SOURCE_AGPS_MSB))) {
         mm_dbus_method_invocation_return_error_literal (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_UNSUPPORTED,
@@ -1109,14 +1105,14 @@ handle_set_supl_server_auth_ready (MMBaseModem *self,
 }
 
 static gboolean
-handle_set_supl_server (MmGdbusModemLocation *skeleton,
+handle_set_supl_server (MmGdbusModemLocation  *skeleton,
                         GDBusMethodInvocation *invocation,
-                        const gchar *supl,
+                        const gchar           *supl,
-                        MMIfaceModemLocation *self)
+                        MMIfaceModemLocation  *self)
 {
     HandleSetSuplServerContext *ctx;
 
-    ctx = g_slice_new (HandleSetSuplServerContext);
+    ctx = g_slice_new0 (HandleSetSuplServerContext);
     ctx->skeleton = g_object_ref (skeleton);
     ctx->invocation = g_object_ref (invocation);
     ctx->self = g_object_ref (self);
@@ -1160,7 +1156,6 @@ inject_assistance_data_ready (MMIfaceModemLocation              *self,
         mm_dbus_method_invocation_take_error (ctx->invocation, error);
     else
         mm_gdbus_modem_location_complete_inject_assistance_data (ctx->skeleton, ctx->invocation);
-
     handle_inject_assistance_data_context_free (ctx);
 }
 
@@ -1214,7 +1209,7 @@ handle_inject_assistance_data (MmGdbusModemLocation  *skeleton,
 {
     HandleInjectAssistanceDataContext *ctx;
 
-    ctx = g_slice_new (HandleInjectAssistanceDataContext);
+    ctx = g_slice_new0 (HandleInjectAssistanceDataContext);
     ctx->skeleton   = g_object_ref (skeleton);
     ctx->invocation = g_object_ref (invocation);
     ctx->self       = g_object_ref (self);
@@ -1231,9 +1226,9 @@ handle_inject_assistance_data (MmGdbusModemLocation  *skeleton,
 /*****************************************************************************/
 
 typedef struct {
-    MmGdbusModemLocation *skeleton;
+    MmGdbusModemLocation  *skeleton;
     GDBusMethodInvocation *invocation;
-    MMIfaceModemLocation *self;
+    MMIfaceModemLocation  *self;
     guint rate;
 } HandleSetGpsRefreshRateContext;
 
@@ -1247,12 +1242,11 @@ handle_set_gps_refresh_rate_context_free (HandleSetGpsRefreshRateContext *ctx)
 }
 
 static void
-handle_set_gps_refresh_rate_auth_ready (MMBaseModem *self,
+handle_set_gps_refresh_rate_auth_ready (MMBaseModem                    *self,
-                                        GAsyncResult *res,
+                                        GAsyncResult                   *res,
                                         HandleSetGpsRefreshRateContext *ctx)
 {
     GError *error = NULL;
-    MMModemState modem_state;
 
     if (!mm_base_modem_authorize_finish (self, res, &error)) {
         mm_dbus_method_invocation_take_error (ctx->invocation, error);
@@ -1260,17 +1254,6 @@ handle_set_gps_refresh_rate_auth_ready (MMBaseModem *self,
         return;
     }
 
-    modem_state = MM_MODEM_STATE_UNKNOWN;
-    g_object_get (self,
-                  MM_IFACE_MODEM_STATE, &modem_state,
-                  NULL);
-    if (modem_state < MM_MODEM_STATE_ENABLED) {
-        mm_dbus_method_invocation_return_error_literal (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_WRONG_STATE,
-                                                        "Cannot set SUPL server: device not yet enabled");
-        handle_set_gps_refresh_rate_context_free (ctx);
-        return;
-    }
-
     /* If GPS is NOT supported, set error */
     if (!(mm_gdbus_modem_location_get_capabilities (ctx->skeleton) & ((MM_MODEM_LOCATION_SOURCE_GPS_RAW |
                                                                        MM_MODEM_LOCATION_SOURCE_GPS_NMEA)))) {
@@ -1287,14 +1270,14 @@ handle_set_gps_refresh_rate_auth_ready (MMBaseModem *self,
 }
 
 static gboolean
-handle_set_gps_refresh_rate (MmGdbusModemLocation *skeleton,
+handle_set_gps_refresh_rate (MmGdbusModemLocation  *skeleton,
                              GDBusMethodInvocation *invocation,
-                             guint rate,
+                             guint                  rate,
-                             MMIfaceModemLocation *self)
+                             MMIfaceModemLocation  *self)
 {
     HandleSetGpsRefreshRateContext *ctx;
 
-    ctx = g_slice_new (HandleSetGpsRefreshRateContext);
+    ctx = g_slice_new0 (HandleSetGpsRefreshRateContext);
     ctx->skeleton = g_object_ref (skeleton);
     ctx->invocation = g_object_ref (invocation);
     ctx->self = g_object_ref (self);
@@ -1311,9 +1294,9 @@ handle_set_gps_refresh_rate (MmGdbusModemLocation *skeleton,
 /*****************************************************************************/
 
 typedef struct {
-    MmGdbusModemLocation *skeleton;
+    MmGdbusModemLocation  *skeleton;
     GDBusMethodInvocation *invocation;
-    MMIfaceModemLocation *self;
+    MMIfaceModemLocation  *self;
 } HandleGetLocationContext;
 
 static void
@@ -1322,17 +1305,16 @@ handle_get_location_context_free (HandleGetLocationContext *ctx)
     g_object_unref (ctx->skeleton);
     g_object_unref (ctx->invocation);
     g_object_unref (ctx->self);
-    g_free (ctx);
+    g_slice_free (HandleGetLocationContext, ctx);
 }
 
 static void
-handle_get_location_auth_ready (MMBaseModem *self,
+handle_get_location_auth_ready (MMBaseModem              *self,
-                                GAsyncResult *res,
+                                GAsyncResult             *res,
                                 HandleGetLocationContext *ctx)
 {
-    MMModemState modem_state;
     LocationContext *location_ctx;
-    GError *error = NULL;
+    GError          *error = NULL;
 
     if (!mm_base_modem_authorize_finish (self, res, &error)) {
         mm_dbus_method_invocation_take_error (ctx->invocation, error);
@@ -1340,17 +1322,6 @@ handle_get_location_auth_ready (MMBaseModem *self,
         return;
     }
 
-    modem_state = MM_MODEM_STATE_UNKNOWN;
-    g_object_get (self,
-                  MM_IFACE_MODEM_STATE, &modem_state,
-                  NULL);
-    if (modem_state < MM_MODEM_STATE_ENABLED) {
-        mm_dbus_method_invocation_return_error_literal (ctx->invocation, MM_CORE_ERROR, MM_CORE_ERROR_WRONG_STATE,
-                                                        "Cannot get location: device not yet enabled");
-        handle_get_location_context_free (ctx);
-        return;
-    }
-
     location_ctx = get_location_context (ctx->self);
     mm_gdbus_modem_location_complete_get_location (
         ctx->skeleton,
@@ -1364,13 +1335,13 @@ handle_get_location_auth_ready (MMBaseModem *self,
 }
 
 static gboolean
-handle_get_location (MmGdbusModemLocation *skeleton,
+handle_get_location (MmGdbusModemLocation  *skeleton,
                      GDBusMethodInvocation *invocation,
-                     MMIfaceModemLocation *self)
+                     MMIfaceModemLocation  *self)
 {
     HandleGetLocationContext *ctx;
 
-    ctx = g_new (HandleGetLocationContext, 1);
+    ctx = g_slice_new0 (HandleGetLocationContext);
     ctx->skeleton = g_object_ref (skeleton);
     ctx->invocation = g_object_ref (invocation);
     ctx->self = g_object_ref (self);
@@ -1450,6 +1421,10 @@ interface_disabling_step (GTask *task)
         /* fall through */
 
     case DISABLING_STEP_DISABLE_GATHERING:
+        /* We disable all sources here. It is true that the user may have enabled GPS
+         * early before getting the modem enabled, and that we may have left it active
+         * once the modem transitions to enabled state, but for the disabling phase
+         * we reset everything. */
         setup_gathering (self,
                          MM_MODEM_LOCATION_SOURCE_NONE,
                          (GAsyncReadyCallback)disabling_location_gathering_ready,
@@ -1573,6 +1548,7 @@ interface_enabling_step (GTask *task)
 
     case ENABLING_STEP_ENABLE_GATHERING: {
         MMModemLocationSource default_sources;
+        MMModemLocationSource currently_enabled;
 
         /* By default, we'll enable all NON-GPS sources */
         default_sources = mm_gdbus_modem_location_get_capabilities (ctx->skeleton);
@@ -1582,8 +1558,11 @@ interface_enabling_step (GTask *task)
                              MM_MODEM_LOCATION_SOURCE_AGPS_MSA |
                              MM_MODEM_LOCATION_SOURCE_AGPS_MSB);
 
+        /* If standalone GPS was already enabled, we keep it enabled */
+        currently_enabled = mm_gdbus_modem_location_get_enabled (ctx->skeleton);
+
         setup_gathering (self,
-                         default_sources,
+                         default_sources | currently_enabled,
                          (GAsyncReadyCallback)enabling_location_gathering_ready,
                          task);
         return;