Merge pull request #8745 from thinkyhead/bf1_sync_M420_M852

[1.1.x] M852 skew changes position. And, position change reporting.

Marlin/Marlin.h

 #endif
 
 #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
-  void set_z_fade_height(const float zfh);
+  void set_z_fade_height(const float zfh, const bool do_report=true);
 #endif
 
 #if ENABLED(X_DUAL_ENDSTOPS)

Marlin/Marlin_main.cpp

   #include "ubl.h"
   extern bool defer_return_to_status;
   unified_bed_leveling ubl;
-  #define UBL_MESH_VALID !( ( ubl.z_values[0][0] == ubl.z_values[0][1] && ubl.z_values[0][1] == ubl.z_values[0][2] \
-                           && ubl.z_values[1][0] == ubl.z_values[1][1] && ubl.z_values[1][1] == ubl.z_values[1][2] \
-                           && ubl.z_values[2][0] == ubl.z_values[2][1] && ubl.z_values[2][1] == ubl.z_values[2][2] \
-                           && ubl.z_values[0][0] == 0 && ubl.z_values[1][0] == 0 && ubl.z_values[2][0] == 0 )  \
-                           || isnan(ubl.z_values[0][0]))
 #endif
 
 #if ENABLED(CNC_COORDINATE_SYSTEMS)
           // so compensation will give the right stepper counts.
           planner.unapply_leveling(current_position);
 
+        SYNC_PLAN_POSITION_KINEMATIC();
+
       #endif // ABL
     }
   }
 
   #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
 
-    void set_z_fade_height(const float zfh) {
+    void set_z_fade_height(const float zfh, const bool do_report/*=true*/) {
+
+      if (planner.z_fade_height == zfh) return; // do nothing if no change
 
       const bool level_active = planner.leveling_active;
 
       planner.set_z_fade_height(zfh);
 
       if (level_active) {
+        const float oldpos[] = { current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS] };
         #if ENABLED(AUTO_BED_LEVELING_UBL)
           set_bed_leveling_enabled(true);  // turn back on after changing fade height
         #else
               Z_AXIS
             #endif
           );
+          SYNC_PLAN_POSITION_KINEMATIC();
         #endif
+        if (do_report && memcmp(oldpos, current_position, sizeof(oldpos)))
+          report_current_position();
       }
     }
 
               bed_level_virt_interpolate();
             #endif
             set_bed_leveling_enabled(abl_should_enable);
+            report_current_position();
           }
           return;
         } // parser.seen('W')
    */
   inline void gcode_M420() {
 
+    const float oldpos[] = { current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS] };
+
     #if ENABLED(AUTO_BED_LEVELING_UBL)
 
       // L to load a mesh from the EEPROM
       // L to load a mesh from the EEPROM
       if (parser.seen('L') || parser.seen('V')) {
         ubl.display_map(0);  // Currently only supports one map type
-        SERIAL_ECHOLNPAIR("UBL_MESH_VALID = ", UBL_MESH_VALID);
+        SERIAL_ECHOLNPAIR("ubl.mesh_is_valid = ", ubl.mesh_is_valid());
         SERIAL_ECHOLNPAIR("ubl.storage_slot = ", ubl.storage_slot);
       }
 
       #endif
     }
 
-    const bool to_enable = parser.boolval('S');
-    if (parser.seen('S'))
-      set_bed_leveling_enabled(to_enable);
-
     #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
-      if (parser.seen('Z')) set_z_fade_height(parser.value_linear_units());
+      if (parser.seen('Z')) set_z_fade_height(parser.value_linear_units(), false);
     #endif
 
+    bool to_enable = false;
+    if (parser.seen('S')) {
+      to_enable = parser.value_bool();
+      set_bed_leveling_enabled(to_enable);
+    }
+
     const bool new_status = planner.leveling_active;
 
     if (to_enable && !new_status) {
       else
         SERIAL_ECHOLNPGM(MSG_OFF);
     #endif
+
+    // Report change in position
+    if (memcmp(oldpos, current_position, sizeof(oldpos)))
+      report_current_position();
   }
 #endif
 
    *  K[yz_factor] - New YZ skew factor
    */
   inline void gcode_M852() {
-    const bool ijk = parser.seen('I') || parser.seen('S')
-      #if ENABLED(SKEW_CORRECTION_FOR_Z)
-        || parser.seen('J') || parser.seen('K')
-      #endif
-    ;
-    bool badval = false;
+    uint8_t ijk = 0, badval = 0, setval = 0;
 
     if (parser.seen('I') || parser.seen('S')) {
+      ++ijk;
       const float value = parser.value_linear_units();
-      if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX))
-        planner.xy_skew_factor = value;
+      if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX)) {
+        if (planner.xy_skew_factor != value) {
+          planner.xy_skew_factor = value;
+          ++setval;
+        }
+      }
       else
-        badval = true;
+        ++badval;
     }
 
     #if ENABLED(SKEW_CORRECTION_FOR_Z)
 
       if (parser.seen('J')) {
+        ++ijk;
         const float value = parser.value_linear_units();
-        if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX))
-          planner.xz_skew_factor = value;
+        if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX)) {
+          if (planner.xz_skew_factor != value) {
+            planner.xz_skew_factor = value;
+            ++setval;
+          }
+        }
         else
-          badval = true;
+          ++badval;
       }
 
       if (parser.seen('K')) {
+        ++ijk;
         const float value = parser.value_linear_units();
-        if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX))
-          planner.yz_skew_factor = value;
+        if (WITHIN(value, SKEW_FACTOR_MIN, SKEW_FACTOR_MAX)) {
+          if (planner.yz_skew_factor != value) {
+            planner.yz_skew_factor = value;
+            ++setval;
+          }
+        }
         else
-          badval = true;
+          ++badval;
       }
 
     #endif
     if (badval)
       SERIAL_ECHOLNPGM(MSG_SKEW_MIN " " STRINGIFY(SKEW_FACTOR_MIN) " " MSG_SKEW_MAX " " STRINGIFY(SKEW_FACTOR_MAX));
 
+    // When skew is changed the current position changes
+    if (setval) {
+      set_current_from_steppers_for_axis(ALL_AXES);
+      SYNC_PLAN_POSITION_KINEMATIC();
+      report_current_position();
+    }
+
     if (!ijk) {
       SERIAL_ECHO_START();
       SERIAL_ECHOPAIR(MSG_SKEW_FACTOR " XY: ", planner.xy_skew_factor);
  * Set the current_position for an axis based on
  * the stepper positions, removing any leveling that
  * may have been applied.
+ *
+ * To prevent small shifts in axis position always call
+ * SYNC_PLAN_POSITION_KINEMATIC after updating axes with this.
+ *
+ * To keep hosts in sync, always call report_current_position
+ * after updating the current_position.
  */
 void set_current_from_steppers_for_axis(const AxisEnum axis) {
   get_cartesian_from_steppers();

Marlin/configuration_store.cpp

   float new_z_fade_height;
 #endif
 
-#if ENABLED(CNC_COORDINATE_SYSTEMS)
-  bool position_changed;
-#endif
-
 /**
  * Post-process after Retrieve or Reset
  */
 void MarlinSettings::postprocess() {
+  const float oldpos[] = { current_position[X_AXIS], current_position[Y_AXIS], current_position[Z_AXIS] };
+
   // steps per s2 needs to be updated to agree with units per s2
   planner.reset_acceleration_rates();
 
     recalc_delta_settings();
   #endif
 
-  // Refresh steps_to_mm with the reciprocal of axis_steps_per_mm
-  // and init stepper.count[], planner.position[] with current_position
-  planner.refresh_positioning();
-
   #if ENABLED(PIDTEMP)
     thermalManager.updatePID();
   #endif
   #endif
 
   #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
-    set_z_fade_height(new_z_fade_height);
+    set_z_fade_height(new_z_fade_height, false); // false = no report
   #endif
 
   #if ENABLED(AUTO_BED_LEVELING_BILINEAR)
     stepper.refresh_motor_power();
   #endif
 
-  #if ENABLED(CNC_COORDINATE_SYSTEMS)
-    if (position_changed) {
-      report_current_position();
-      position_changed = false;
-    }
-  #endif
+  // Refresh steps_to_mm with the reciprocal of axis_steps_per_mm
+  // and init stepper.count[], planner.position[] with current_position
+  planner.refresh_positioning();
+
+  // Various factors can change the current position
+  if (memcmp(oldpos, current_position, sizeof(oldpos)))
+    report_current_position();
 }
 
 #if ENABLED(EEPROM_SETTINGS)
       //
 
       #if ENABLED(CNC_COORDINATE_SYSTEMS)
-        position_changed = select_coordinate_system(-1); // Go back to machine space
+        (void)select_coordinate_system(-1); // Go back to machine space
         EEPROM_READ(coordinate_system);                  // 27 floats
       #else
         for (uint8_t q = 27; q--;) EEPROM_READ(dummy);

Marlin/ubl.cpp

   volatile int unified_bed_leveling::encoder_diff;
 
   unified_bed_leveling::unified_bed_leveling() {
-    ubl_cnt++;  // Debug counter to insure we only have one UBL object present in memory.  We can eliminate this (and all references to ubl_cnt) very soon.
+    ubl_cnt++;  // Debug counter to ensure we only have one UBL object present in memory.  We can eliminate this (and all references to ubl_cnt) very soon.
     reset();
   }
 
   void unified_bed_leveling::reset() {
+    const bool was_enabled = planner.leveling_active;
     set_bed_leveling_enabled(false);
     storage_slot = -1;
     #if ENABLED(ENABLE_LEVELING_FADE_HEIGHT)
       planner.set_z_fade_height(10.0);
     #endif
     ZERO(z_values);
+    if (was_enabled) report_current_position();
   }
 
   void unified_bed_leveling::invalidate() {