2 files changed, 25 insertions(+), 6 deletions(-)

M module-cellular/at/Commands.hpp
M module-services/service-cellular/ServiceCellular.cpp

@@ 1,4 1,4 @@
-// Copyright (c) 2017-2021, Mudita Sp. z.o.o. All rights reserved.
+// Copyright (c) 2017-2022, Mudita Sp. z.o.o. All rights reserved.
 // For licensing, see https://github.com/mudita/MuditaOS/LICENSE.md
 
 #pragma once


@@ 145,4 145,7 @@ namespace at
     };
 
     std::vector<AT> getCommadsSet(commadsSet set);
+
+    constexpr auto AtCmdMaxRetries   = 3;
+    constexpr auto AtCmdRetryDelayMS = 50;
 }; // namespace at

@@ 912,8 912,6 @@ std::optional<std::shared_ptr<sys::Message>> ServiceCellular::identifyNotificati
 
 auto ServiceCellular::receiveSMS(std::string messageNumber) -> bool
 {
-    constexpr auto ucscSetMaxRetries = 3;
-
     auto retVal = true;
 
     auto channel = cmux->get(CellularMux::Channel::Commands);


@@ 923,7 921,7 @@ auto ServiceCellular::receiveSMS(std::string messageNumber) -> bool
     }
 
     auto ucscSetRetries = 0;
-    while (ucscSetRetries < ucscSetMaxRetries) {
+    while (ucscSetRetries < at::AtCmdMaxRetries) {
         if (!channel->cmd(at::AT::SMS_UCSC2)) {
             ++ucscSetRetries;
             LOG_ERROR("Could not set UCS2 charset mode for TE. Retry %d", ucscSetRetries);


@@ 948,8 946,26 @@ auto ServiceCellular::receiveSMS(std::string messageNumber) -> bool
     std::string messageRawBody;
     UTF8 receivedNumber;
     const auto &cmd = at::factory(at::AT::QCMGR);
-    auto ret        = channel->cmd(cmd + messageNumber, cmd.getTimeout());
-    if (!ret) {
+    at::Result ret;
+    auto qcmgrRetries = 0;
+
+    while (qcmgrRetries < at::AtCmdMaxRetries) {
+        ret = channel->cmd(cmd + messageNumber, cmd.getTimeout());
+        if (!ret) {
+            ++qcmgrRetries;
+            LOG_ERROR("Could not read text message. Retry %d", qcmgrRetries);
+            // There are cases where +QCMGR command is issued to soon after +CMTI URC,
+            // and modem is still busy processing messages. This results with an error
+            // and some garbage frame. To work around this, we delay a bit and retry +QCMGR
+            // to get the message.
+            vTaskDelay(at::AtCmdRetryDelayMS);
+        }
+        else {
+            break;
+        }
+    }
+
+    if (!ret || qcmgrRetries == at::AtCmdMaxRetries) {
         LOG_ERROR("!!!! Could not read text message !!!!");
         retVal = false;
     }