An attempt at fixing the retry. Discussion needed.

Firmware/mmu2.cpp

@@ -112,6 +112,7 @@ MMU2::MMU2()
     , loadFilamentStarted(false)
     , unloadFilamentStarted(false)
     , loadingToNozzle(false)
+    , inAutoRetry(false)
 {
     ResetRetryAttempts();
 }
@@ -230,11 +231,14 @@ bool MMU2::RetryIfPossible(uint16_t ec){
         SetButtonResponse(ButtonOperations::Retry);
         // check, that Retry is actually allowed on that operation
         if( ButtonAvailable(ec) != NoButton ){
+            inAutoRetry = true;
             SERIAL_ECHOLNPGM("RetryButtonPressed");
-            --retryAttempts; // "used" one retry attempt
+            // We don't decrement until the button is acknowledged by the MMU.
+            //--retryAttempts; // "used" one retry attempt
             return true;
         }
     }
+    inAutoRetry = false;
     return false;
 }
 
@@ -243,6 +247,14 @@ void MMU2::ResetRetryAttempts(){
     retryAttempts = 3;
 }
 
+void MMU2::DecrementRetryAttempts(){
+    if (inAutoRetry && retryAttempts)
+    {
+        SERIAL_ECHOLNPGM("DecrementRetryAttempts");
+        retryAttempts--;
+    }
+}
+
 bool MMU2::tool_change(uint8_t index) {
     if( ! WaitForMMUReady())
         return false;
@@ -607,7 +619,8 @@ void MMU2::CheckUserInput(){
     case Left:
     case Middle:
     case Right:
-        SERIAL_ECHOLNPGM("CheckUserInput-btnLMR");
+        SERIAL_ECHOPGM("CheckUserInput-btnLMR ");
+        SERIAL_ECHOLN(btn);
         ResumeHotendTemp(); // Recover the hotend temp before we attempt to do anything else...
         Button(btn);
         break;
@@ -655,7 +668,7 @@ void MMU2::manage_response(const bool move_axes, const bool turn_off_nozzle) {
             if (!nozzleTimeout.running())
             {
                 nozzleTimeout.start();
-                LogEchoEvent(" Cooling Timeout started");
+                LogEchoEvent("Cooling Timeout started");
             } 
             else if (nozzleTimeout.expired(DEFAULT_SAFETYTIMER_TIME_MINS*60*1000ul)) // mins->msec. TODO: do we use the global or have our own independent timeout
             {
@@ -676,13 +689,20 @@ void MMU2::manage_response(const bool move_axes, const bool turn_off_nozzle) {
             // command/operation completed, let Marlin continue its work
             // the E may have some more moves to finish - wait for them
             ResumeUnpark(); // We can now travel back to the tower or wherever we were when we saved.
+            ResetRetryAttempts(); // Reset the retry counter.
             st_synchronize(); 
             return;
         case VersionMismatch: // this basically means the MMU will be disabled until reconnected
             CheckUserInput();
             return;
-        case CommunicationTimeout:
         case CommandError:
+            // Don't proceed to the park/save if we are doing an autoretry.
+            if (inAutoRetry)
+            {
+                continue;
+            }
+            /* FALLTHRU */
+        case CommunicationTimeout:
         case ProtocolError:
             SaveAndPark(move_axes, turn_off_nozzle); // and wait for the user to resolve the problem
             CheckUserInput();

Firmware/mmu2.h

@@ -168,10 +168,13 @@ public:
     /// Automagically "press" a Retry button if we have any retry attempts left
     bool RetryIfPossible(uint16_t ec);
 
-    /// Reset the retryAttempts back to the default value
-    void ResetRetryAttempts();
+    /// Decrement the retry attempts, if in a retry. 
+    // Called by the MMU protocol when a sent button is acknowledged.
+    void DecrementRetryAttempts();
 
 private:
+    /// Reset the retryAttempts back to the default value
+    void ResetRetryAttempts();
     /// Perform software self-reset of the MMU (sends an X0 command)
     void ResetX0();
     
@@ -261,6 +264,8 @@ private:
     bool loadingToNozzle;
     
     uint8_t retryAttempts;
+
+    bool inAutoRetry;
 };
 
 /// following Marlin's way of doing stuff - one and only instance of MMU implementation in the code base

Firmware/mmu2_protocol_logic.cpp

@@ -261,10 +261,15 @@ StepStatus Command::Step() {
         return ProcessFINDAReqSent(Processing, State::Wait);
     case State::ButtonSent:{
         // button is never confirmed ... may be it should be
-        // auto expmsg = logic->ExpectingMessage(linkLayerTimeout);
-        // if (expmsg != MessageReady)
-        //     return expmsg;
-        SendQuery();
+        auto expmsg = logic->ExpectingMessage(linkLayerTimeout);
+        if (expmsg != MessageReady)
+            return expmsg;
+        if (logic->rsp.paramCode == ResponseMsgParamCodes::Accepted)
+        {
+            // Button was accepted, decrement the retry.
+            mmu2.DecrementRetryAttempts();
+        }
+        SendAndUpdateFilamentSensor();
         } break;
     default:
         return ProtocolError;

Firmware/mmu2_reporting.cpp

@@ -205,7 +205,6 @@ void ReportErrorHook(uint16_t ec, uint8_t res) {
         // a button was pushed on the MMU and the LCD should
         // dismiss the error screen until MMU raises a new error
         ReportErrorHookState = ReportErrorHookStates::DISMISS_ERROR_SCREEN;
-        mmu2.ResetRetryAttempts();
     } else {
         // attempt an automatic Retry button
         if( ReportErrorHookState == ReportErrorHookStates::MONITOR_SELECTION ){