Internal G29N for G28+G29 (#20800)

Marlin/Configuration_adv.h

   //#define USER_SCRIPT_RETURN  // Return to status screen after a script
 
   #define USER_DESC_1 "Home & UBL Info"
-  #define USER_GCODE_1 "G28\nG29 W"
+  #define USER_GCODE_1 "G29NW"
 
   #define USER_DESC_2 "Preheat for " PREHEAT_1_LABEL
   #define USER_GCODE_2 "M140 S" STRINGIFY(PREHEAT_1_TEMP_BED) "\nM104 S" STRINGIFY(PREHEAT_1_TEMP_HOTEND)
   #define USER_GCODE_3 "M140 S" STRINGIFY(PREHEAT_2_TEMP_BED) "\nM104 S" STRINGIFY(PREHEAT_2_TEMP_HOTEND)
 
   #define USER_DESC_4 "Heat Bed/Home/Level"
-  #define USER_GCODE_4 "M140 S" STRINGIFY(PREHEAT_2_TEMP_BED) "\nG28\nG29"
+  #define USER_GCODE_4 "M140 S" STRINGIFY(PREHEAT_2_TEMP_BED) "\nG29N"
 
   #define USER_DESC_5 "Home & Info"
   #define USER_GCODE_5 "G28\nM503"

Marlin/src/feature/bedlevel/ubl/ubl_G29.cpp

     // Check for commands that require the printer to be homed
     if (may_move) {
       planner.synchronize();
-      if (axes_should_home()) gcode.home_all_axes();
+      // Send 'N' to force homing before G29 (internal only)
+      if (axes_should_home() || parser.seen('N')) gcode.home_all_axes();
       TERN_(HAS_MULTI_HOTEND, if (active_extruder) tool_change(0));
     }
 

Marlin/src/gcode/bedlevel/abl/G29.cpp

          no_action = seenA || seenQ,
               faux = ENABLED(DEBUG_LEVELING_FEATURE) && DISABLED(PROBE_MANUALLY) ? parser.boolval('C') : no_action;
 
-  // Don't allow auto-leveling without homing first
-  if (homing_needed_error()) G29_RETURN(false);
-
   if (!no_action && planner.leveling_active && parser.boolval('O')) { // Auto-level only if needed
     if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("> Auto-level not needed, skip");
     G29_RETURN(false);
   }
 
+  // Send 'N' to force homing before G29 (internal only)
+  if (parser.seen('N'))
+    gcode.process_subcommands_now_P(TERN(G28_L0_ENSURES_LEVELING_OFF, PSTR("G28L0"), G28_STR));
+
+  // Don't allow auto-leveling without homing first
+  if (homing_needed_error()) G29_RETURN(false);
+
   // Define local vars 'static' for manual probing, 'auto' otherwise
   #define ABL_VAR TERN_(PROBE_MANUALLY, static)
 
 
   #if ENABLED(AUTO_BED_LEVELING_LINEAR)
     struct linear_fit_data lsf_results;
-    incremental_LSF_reset(&lsf_results);
   #endif
 
   /**
 
     #if ENABLED(AUTO_BED_LEVELING_LINEAR)
 
+      incremental_LSF_reset(&lsf_results);
+
       do_topography_map = verbose_level > 2 || parser.boolval('T');
 
       // X and Y specify points in each direction, overriding the default

Marlin/src/gcode/bedlevel/mbl/G29.cpp

       mbl.reset();
       mbl_probe_index = 0;
       if (!ui.wait_for_move) {
-        queue.inject_P(PSTR("G28\nG29 S2"));
+        queue.inject_P(parser.seen('N') ? PSTR("G28" TERN(G28_L0_ENSURES_LEVELING_OFF, "L0", "") "\nG29S2") : PSTR("G29S2"));
         return;
       }
       state = MeshNext;

Marlin/src/gcode/feature/pause/M600.cpp

 
   #if ENABLED(HOME_BEFORE_FILAMENT_CHANGE)
     // If needed, home before parking for filament change
-    if (!all_axes_trusted()) home_all_axes();
+    if (!all_axes_trusted()) home_all_axes(true);
   #endif
 
   #if HAS_MULTI_EXTRUDER

Marlin/src/gcode/gcode.h

   static void process_subcommands_now_P(PGM_P pgcode);
   static void process_subcommands_now(char * gcode);
 
-  static inline void home_all_axes() {
+  static inline void home_all_axes(const bool keep_leveling=false) {
     extern const char G28_STR[];
-    process_subcommands_now_P(G28_STR);
+    process_subcommands_now_P(keep_leveling ? G28_STR : TERN(G28_L0_ENSURES_LEVELING_OFF, PSTR("G28L0"), G28_STR));
   }
 
   #if EITHER(HAS_AUTO_REPORTING, HOST_KEEPALIVE_FEATURE)

Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp

 
               case '2': // "<02ABL>"
                 SERIAL_ECHOLNPGM("Special Menu: Auto Bed Leveling");
-                ExtUI::injectCommands_P(PSTR("G28\nG29"));
+                ExtUI::injectCommands_P(PSTR("G29N"));
                 break;
 
               case '3': // "<03HtendPID>"

Marlin/src/lcd/extui/lib/mks_ui/draw_ui.cpp

 extern void LCD_IO_WriteData(uint16_t RegValue);
 
 static const char custom_gcode_command[][100] = {
-  "G28\nG29\nM500",
+  "G29N\nM500",
   "G28",
   "G28",
   "G28",

Marlin/src/lcd/menu/menu_bed_corners.cpp

   void _lcd_draw_level_prompt() {
     if (!ui.should_draw()) return;
     MenuItem_confirm::confirm_screen(
-      []{ queue.inject_P(TERN(HAS_LEVELING, PSTR("G28\nG29"), G28_STR));
+      []{ queue.inject_P(TERN(HAS_LEVELING, PSTR("G29N"), G28_STR));
           ui.return_to_status();
       }
       , []{ ui.goto_previous_screen_no_defer(); }

Marlin/src/lcd/menu/menu_bed_leveling.cpp

     SUBMENU(MSG_LEVEL_BED, _lcd_level_bed_continue);
   #else
     // Automatic leveling can just run the G-code
-    GCODES_ITEM(MSG_LEVEL_BED, is_homed ? PSTR("G29") : PSTR("G28\nG29"));
+    GCODES_ITEM(MSG_LEVEL_BED, is_homed ? PSTR("G29") : PSTR("G29N"));
   #endif
 
   #if ENABLED(MESH_EDIT_MENU)

Marlin/src/lcd/menu/menu_motion.cpp

   #elif HAS_LEVELING && DISABLED(SLIM_LCD_MENUS)
 
     #if DISABLED(PROBE_MANUALLY)
-      GCODES_ITEM(MSG_LEVEL_BED, PSTR("G28\nG29"));
+      GCODES_ITEM(MSG_LEVEL_BED, PSTR("G29N"));
     #endif
 
     if (all_axes_homed() && leveling_is_valid()) {

Marlin/src/lcd/menu/menu_ubl.cpp

   #endif // PREHEAT_COUNT
 
   SUBMENU(MSG_UBL_BUILD_CUSTOM_MESH, _lcd_ubl_custom_mesh);
-  GCODES_ITEM(MSG_UBL_BUILD_COLD_MESH, PSTR("G28\nG29P1"));
+  GCODES_ITEM(MSG_UBL_BUILD_COLD_MESH, PSTR("G29NP1"));
   SUBMENU(MSG_UBL_FILLIN_MESH, _menu_ubl_fillin);
   GCODES_ITEM(MSG_UBL_CONTINUE_MESH, PSTR("G29P1C"));
   ACTION_ITEM(MSG_UBL_INVALIDATE_ALL, _lcd_ubl_invalidate);
   void _lcd_ubl_step_by_step() {
     START_MENU();
     BACK_ITEM(MSG_UBL_LEVEL_BED);
-    GCODES_ITEM(MSG_UBL_1_BUILD_COLD_MESH, PSTR("G28\nG29P1"));
+    GCODES_ITEM(MSG_UBL_1_BUILD_COLD_MESH, PSTR("G29NP1"));
     GCODES_ITEM(MSG_UBL_2_SMART_FILLIN, PSTR("G29P3T0"));
     SUBMENU(MSG_UBL_3_VALIDATE_MESH_MENU, _lcd_ubl_validate_mesh);
     GCODES_ITEM(MSG_UBL_4_FINE_TUNE_ALL, PSTR("G29P4R999T"));