Only use slow homing speed where applicable (#15640)

Marlin/src/gcode/calibrate/G28.cpp

 
 #endif // Z_SAFE_HOMING
 
+#if ENABLED(IMPROVE_HOMING_RELIABILITY)
+
+  slow_homing_t begin_slow_homing() {
+    slow_homing_t slow_homing{0};
+    slow_homing.acceleration.set(planner.settings.max_acceleration_mm_per_s2[X_AXIS],
+                                 planner.settings.max_acceleration_mm_per_s2[Y_AXIS]);
+    planner.settings.max_acceleration_mm_per_s2[X_AXIS] = 100;
+    planner.settings.max_acceleration_mm_per_s2[Y_AXIS] = 100;
+    #if HAS_CLASSIC_JERK
+      slow_homing.jerk_xy = planner.max_jerk;
+      planner.max_jerk.set(0, 0);
+    #endif
+    planner.reset_acceleration_rates();
+    return slow_homing;
+  }
+
+  void end_slow_homing(const slow_homing_t &slow_homing) {
+    planner.settings.max_acceleration_mm_per_s2[X_AXIS] = slow_homing.acceleration.x;
+    planner.settings.max_acceleration_mm_per_s2[Y_AXIS] = slow_homing.acceleration.y;
+    #if HAS_CLASSIC_JERK
+      planner.max_jerk = slow_homing.jerk_xy;
+    #endif
+    planner.reset_acceleration_rates();
+  }
+
+#endif // IMPROVE_HOMING_RELIABILITY
+
 /**
  * G28: Home all axes according to settings
  *
   #endif
 
   #if ENABLED(IMPROVE_HOMING_RELIABILITY)
-    slow_homing_t slow_homing{0};
-    slow_homing.acceleration.set(planner.settings.max_acceleration_mm_per_s2[X_AXIS],
-                                 planner.settings.max_acceleration_mm_per_s2[Y_AXIS]);
-    planner.settings.max_acceleration_mm_per_s2[X_AXIS] = 100;
-    planner.settings.max_acceleration_mm_per_s2[Y_AXIS] = 100;
-    #if HAS_CLASSIC_JERK
-      slow_homing.jerk_xy = planner.max_jerk;
-      planner.max_jerk.set(0, 0);
-    #endif
-
-    planner.reset_acceleration_rates();
+    slow_homing_t slow_homing = begin_slow_homing();
   #endif
 
   // Always home with tool 0 active
     home_delta();
     UNUSED(always_home_all);
 
+    #if ENABLED(IMPROVE_HOMING_RELIABILITY)
+      end_slow_homing(slow_homing);
+    #endif
+
   #else // NOT DELTA
 
     const bool homeX = parser.seen('X'), homeY = parser.seen('Y'), homeZ = parser.seen('Z'),
       if (doY) homeaxis(Y_AXIS);
     #endif
 
+    #if ENABLED(IMPROVE_HOMING_RELIABILITY)
+      end_slow_homing(slow_homing);
+    #endif
+
     // Home Z last if homing towards the bed
     #if Z_HOME_DIR < 0
       if (doZ) {
 
     if (dxc_is_duplicating()) {
 
+      #if ENABLED(IMPROVE_HOMING_RELIABILITY)
+        slow_homing = begin_slow_homing();
+      #endif
+
       // Always home the 2nd (right) extruder first
       active_extruder = 1;
       homeaxis(X_AXIS);
 
       dual_x_carriage_mode         = IDEX_saved_mode;
       stepper.set_directions();
+
+      #if ENABLED(IMPROVE_HOMING_RELIABILITY)
+        end_slow_homing(slow_homing);
+      #endif
     }
 
   #endif // DUAL_X_CARRIAGE
     tool_change(old_tool_index, NO_FETCH);
   #endif
 
-  #if ENABLED(IMPROVE_HOMING_RELIABILITY)
-    planner.settings.max_acceleration_mm_per_s2[X_AXIS] = slow_homing.acceleration.x;
-    planner.settings.max_acceleration_mm_per_s2[Y_AXIS] = slow_homing.acceleration.y;
-    #if HAS_CLASSIC_JERK
-      planner.max_jerk = slow_homing.jerk_xy;
-    #endif
-    planner.reset_acceleration_rates();
-  #endif
-
   ui.refresh();
 
   report_current_position();