broadband-modem-mbim: ignore registration set error if NwError=0 reported

Returning an error in the registration set request completely breaks
the async operation requesting the explicit registration, even if the
modem may have already been registered via indications while waiting
for the set request to be completed.

We now ignore the registration set error if it returns a generic
failure with NwError=0, as in certain Qualcomm based devices. We
ignore unconditionally, without explicitly checking if we're
registered or not, because the upper logic will anyway do that.

Fixes https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/723

1 files changed, 18 insertions, 11 deletions

diff --git a/src/mm-broadband-modem-mbim.c b/src/mm-broadband-modem-mbim.c
index 1ebdabe9e..1759db75d 100644
--- a/src/mm-broadband-modem-mbim.c
+++ b/src/mm-broadband-modem-mbim.c
@@ -6393,13 +6393,12 @@ register_state_set_ready (MbimDevice *device,
                           GAsyncResult *res,
                           GTask *task)
 {
-    MMBroadbandModemMbim *self;
-    MbimMessage          *response;
-    GError               *error = NULL;
+    MMBroadbandModemMbim   *self;
+    g_autoptr(MbimMessage)  response = NULL;
+    GError                 *error = NULL;
 
     self = g_task_get_source_object (task);
 
-    response = mbim_device_command_finish (device, res, &error);
     /* According to Mobile Broadband Interface Model specification 1.0,
      * Errata 1, table 10.5.9.8: Status codes for MBIM_CID_REGISTER_STATE,
      * NwError field of MBIM_REGISTRATION_STATE_INFO structure is valid
@@ -6410,9 +6409,8 @@ register_state_set_ready (MbimDevice *device,
      * However, some modems do not set this value to 0 when registered,
      * causing ModemManager to drop to idle state, while modem itself is
      * registered.
-     * Also NwError "0" is defined in 3GPP TS 24.008 as "Unknown error",
-     * not "No error", making it unsuitable as condition for registration check.
      */
+    response = mbim_device_command_finish (device, res, &error);
     if (response &&
         !mbim_message_response_get_result (response,
                                            MBIM_MESSAGE_TYPE_COMMAND_DONE,
@@ -6432,13 +6430,22 @@ register_state_set_ready (MbimDevice *device,
                 NULL, /* provider_name */
                 NULL, /* roaming_text */
                 NULL, /* registration_flag */
-                &error))
-            error = mm_mobile_equipment_error_from_mbim_nw_error (nw_error, self);
+                &error)) {
+            /* NwError "0" is defined in 3GPP TS 24.008 as "Unknown error",
+             * not "No error", making it unsuitable as condition for registration check.
+             * Still, there are certain modems (e.g. Fibocom NL668) that will
+             * report Failure+NwError=0 even after the modem has already reported a
+             * succesful registration via indications after the set operation. If
+             * that is the case, log about it and ignore the error; we are anyway
+             * reloading the registration info after the set, so it should not be
+             * a big issue. */
+            if (nw_error == 0)
+                mm_obj_dbg (self, "ignored failure reported in register operation");
+            else
+                error = mm_mobile_equipment_error_from_mbim_nw_error (nw_error, self);
+        }
     }
 
-    if (response)
-        mbim_message_unref (response);
-
     if (error)
         g_task_return_error (task, error);
     else