🐛 Prevent MPC E-permm overrun in Load Filament (#25531)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/feature/pause.cpp

@@ -234,6 +234,8 @@ bool load_filament(const_float_t slow_load_length/*=0*/, const_float_t fast_load
 
   TERN_(BELTPRINTER, do_blocking_move_to_xy(0.00, 50.00));
 
+  TERN_(MPCTEMP, MPC::e_paused = true);
+
   // Slow Load filament
   if (slow_load_length) unscaled_e_move(slow_load_length, FILAMENT_CHANGE_SLOW_LOAD_FEEDRATE);
 
@@ -297,6 +299,9 @@ bool load_filament(const_float_t slow_load_length/*=0*/, const_float_t fast_load
     } while (TERN0(M600_PURGE_MORE_RESUMABLE, pause_menu_response == PAUSE_RESPONSE_EXTRUDE_MORE));
 
   #endif
+
+  TERN_(MPCTEMP, MPC::e_paused = false);
+
   TERN_(HOST_PROMPT_SUPPORT, hostui.prompt_end());
 
   return true;

Marlin/src/module/temperature.cpp

@@ -319,6 +319,11 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
   hotend_info_t Temperature::temp_hotend[HOTENDS];
   constexpr celsius_t Temperature::hotend_maxtemp[HOTENDS];
 
+  #if ENABLED(MPCTEMP)
+    bool MPC::e_paused; // = false
+    int32_t MPC::e_position; // = 0
+  #endif
+
   // Sanity-check max readable temperatures
   #define CHECK_MAXTEMP_(N,M,S) static_assert( \
     S >= 998 || M <= _MAX(TT_NAME(S)[0].celsius, TT_NAME(S)[COUNT(TT_NAME(S)) - 1].celsius) - HOTEND_OVERSHOOT, \
@@ -588,10 +593,6 @@ PGMSTR(str_t_heating_failed, STR_T_HEATING_FAILED);
 
 volatile bool Temperature::raw_temps_ready = false;
 
-#if ENABLED(MPCTEMP)
-  int32_t Temperature::mpc_e_position; // = 0
-#endif
-
 #define TEMPDIR(N) ((TEMP_SENSOR_##N##_RAW_LO_TEMP) < (TEMP_SENSOR_##N##_RAW_HI_TEMP) ? 1 : -1)
 #define TP_CMP(S,A,B) (TEMPDIR(S) < 0 ? ((A)<(B)) : ((A)>(B)))
 
@@ -1511,14 +1512,14 @@ void Temperature::mintemp_error(const heater_id_t heater_id) {
 
       if (this_hotend) {
         const int32_t e_position = stepper.position(E_AXIS);
-        const float e_speed = (e_position - mpc_e_position) * planner.mm_per_step[E_AXIS] / MPC_dT;
+        const float e_speed = (e_position - MPC::e_position) * planner.mm_per_step[E_AXIS] / MPC_dT;
 
         // The position can appear to make big jumps when, e.g., homing
         if (fabs(e_speed) > planner.settings.max_feedrate_mm_s[E_AXIS])
-          mpc_e_position = e_position;
+          MPC::e_position = e_position;
         else if (e_speed > 0.0f) {  // Ignore retract/recover moves
-          ambient_xfer_coeff += e_speed * mpc.filament_heat_capacity_permm;
+          if (!MPC::e_paused) ambient_xfer_coeff += e_speed * mpc.filament_heat_capacity_permm;
-          mpc_e_position = e_position;
+          MPC::e_position = e_position;
         }
       }
 

Marlin/src/module/temperature.h

@@ -377,7 +377,9 @@ typedef struct { float p, i, d, c, f; } raw_pidcf_t;
 
 #elif ENABLED(MPCTEMP)
 
-  typedef struct {
+  typedef struct MPC {
+    static bool e_paused;               // Pause E filament permm tracking
+    static int32_t e_position;          // For E tracking
     float heater_power;                 // M306 P
     float block_heat_capacity;          // M306 C
     float sensor_responsiveness;        // M306 R
@@ -716,10 +718,6 @@ class Temperature {
       static hotend_watch_t watch_hotend[HOTENDS];
     #endif
 
-    #if ENABLED(MPCTEMP)
-      static int32_t mpc_e_position;
-    #endif
-
     #if HAS_HOTEND
       static temp_range_t temp_range[HOTENDS];
     #endif