🎨 Misc. adjustments, spacing

Marlin/Configuration.h

 //========================== Extensible UI Displays ===========================
 //=============================================================================
 
-//
-// DGUS Touch Display with DWIN OS. (Choose one.)
-// ORIGIN : https://www.aliexpress.com/item/32993409517.html
-// FYSETC : https://www.aliexpress.com/item/32961471929.html
-// MKS    : https://www.aliexpress.com/item/1005002008179262.html
-//
-// Flash display with DGUS Displays for Marlin:
-//  - Format the SD card to FAT32 with an allocation size of 4kb.
-//  - Download files as specified for your type of display.
-//  - Plug the microSD card into the back of the display.
-//  - Boot the display and wait for the update to complete.
-//
-// ORIGIN (Marlin DWIN_SET)
-//  - Download https://github.com/coldtobi/Marlin_DGUS_Resources
-//  - Copy the downloaded DWIN_SET folder to the SD card.
-//
-// FYSETC (Supplier default)
-//  - Download https://github.com/FYSETC/FYSTLCD-2.0
-//  - Copy the downloaded SCREEN folder to the SD card.
-//
-// HIPRECY (Supplier default)
-//  - Download https://github.com/HiPrecy/Touch-Lcd-LEO
-//  - Copy the downloaded DWIN_SET folder to the SD card.
-//
-// MKS (MKS-H43) (Supplier default)
-//  - Download https://github.com/makerbase-mks/MKS-H43
-//  - Copy the downloaded DWIN_SET folder to the SD card.
-//
-// RELOADED (T5UID1)
-//  - Download https://github.com/Desuuuu/DGUS-reloaded/releases
-//  - Copy the downloaded DWIN_SET folder to the SD card.
-//
+/**
+ * DGUS Touch Display with DWIN OS. (Choose one.)
+ * ORIGIN : https://www.aliexpress.com/item/32993409517.html
+ * FYSETC : https://www.aliexpress.com/item/32961471929.html
+ * MKS    : https://www.aliexpress.com/item/1005002008179262.html
+ *
+ * Flash display with DGUS Displays for Marlin:
+ *  - Format the SD card to FAT32 with an allocation size of 4kb.
+ *  - Download files as specified for your type of display.
+ *  - Plug the microSD card into the back of the display.
+ *  - Boot the display and wait for the update to complete.
+ *
+ * ORIGIN (Marlin DWIN_SET)
+ *  - Download https://github.com/coldtobi/Marlin_DGUS_Resources
+ *  - Copy the downloaded DWIN_SET folder to the SD card.
+ *
+ * FYSETC (Supplier default)
+ *  - Download https://github.com/FYSETC/FYSTLCD-2.0
+ *  - Copy the downloaded SCREEN folder to the SD card.
+ *
+ * HIPRECY (Supplier default)
+ *  - Download https://github.com/HiPrecy/Touch-Lcd-LEO
+ *  - Copy the downloaded DWIN_SET folder to the SD card.
+ *
+ * MKS (MKS-H43) (Supplier default)
+ *  - Download https://github.com/makerbase-mks/MKS-H43
+ *  - Copy the downloaded DWIN_SET folder to the SD card.
+ *
+ * RELOADED (T5UID1)
+ *  - Download https://github.com/Desuuuu/DGUS-reloaded/releases
+ *  - Copy the downloaded DWIN_SET folder to the SD card.
+ */
 //#define DGUS_LCD_UI_ORIGIN
 //#define DGUS_LCD_UI_FYSETC
 //#define DGUS_LCD_UI_HIPRECY

Marlin/src/gcode/host/M876.cpp

 
 #include "../../inc/MarlinConfig.h"
 
-#if ENABLED(HOST_PROMPT_SUPPORT) && DISABLED(EMERGENCY_PARSER)
+#if HAS_GCODE_M876
 
 #include "../../feature/host_actions.h"
 #include "../gcode.h"
 
 }
 
-#endif // HOST_PROMPT_SUPPORT && !EMERGENCY_PARSER
+#endif // HAS_GCODE_M876

Marlin/src/inc/Conditionals_adv.h

   #undef SERIAL_XON_XOFF
 #endif
 
+#if ENABLED(HOST_PROMPT_SUPPORT) && DISABLED(EMERGENCY_PARSER)
+  #define HAS_GCODE_M876
+#endif
+
 #if ENABLED(HOST_ACTION_COMMANDS)
   #ifndef ACTION_ON_PAUSE
     #define ACTION_ON_PAUSE   "pause"

Marlin/src/lcd/marlinui.cpp

 #endif
 
 #if LCD_BACKLIGHT_TIMEOUT
+
   uint16_t MarlinUI::lcd_backlight_timeout; // Initialized by settings.load()
   millis_t MarlinUI::backlight_off_ms = 0;
   void MarlinUI::refresh_backlight_timeout() {
     backlight_off_ms = lcd_backlight_timeout ? millis() + lcd_backlight_timeout * 1000UL : 0;
     WRITE(LCD_BACKLIGHT_PIN, HIGH);
   }
+
 #endif
 
 void MarlinUI::init() {

Marlin/src/lcd/menu/menu_configuration.cpp

   #if HAS_LCD_CONTRAST && LCD_CONTRAST_MIN < LCD_CONTRAST_MAX
     EDIT_ITEM_FAST(uint8, MSG_CONTRAST, &ui.contrast, LCD_CONTRAST_MIN, LCD_CONTRAST_MAX, ui.refresh_contrast, true);
   #endif
+
+  //
+  // Set display backlight / sleep timeout
+  //
   #if LCD_BACKLIGHT_TIMEOUT && LCD_BKL_TIMEOUT_MIN < LCD_BKL_TIMEOUT_MAX
     EDIT_ITEM(uint16_4, MSG_LCD_BKL_TIMEOUT, &ui.lcd_backlight_timeout, LCD_BKL_TIMEOUT_MIN, LCD_BKL_TIMEOUT_MAX, ui.refresh_backlight_timeout);
   #endif

Marlin/src/module/settings.cpp

   uint8_t lcd_brightness;                               // M256 B
 
   //
-  // LCD_BACKLIGHT_TIMEOUT
+  // Display Sleep
   //
   #if LCD_BACKLIGHT_TIMEOUT
     uint16_t lcd_backlight_timeout;                     // (G-code needed)
     }
 
     //
-    // LCD Backlight Timeout
+    // LCD Backlight / Sleep Timeout
     //
     #if LCD_BACKLIGHT_TIMEOUT
       EEPROM_WRITE(ui.lcd_backlight_timeout);
       #if ENABLED(USE_CONTROLLER_FAN)
         const controllerFan_settings_t &cfs = controllerFan.settings;
       #else
-        controllerFan_settings_t cfs = controllerFan_defaults;
+        constexpr controllerFan_settings_t cfs = controllerFan_defaults;
       #endif
       EEPROM_WRITE(cfs);
     }
       }
 
       //
-      // LCD Backlight Timeout
+      // LCD Backlight / Sleep Timeout
       //
       #if LCD_BACKLIGHT_TIMEOUT
         EEPROM_READ(ui.lcd_backlight_timeout);
   TERN_(HAS_LCD_BRIGHTNESS, ui.brightness = LCD_BRIGHTNESS_DEFAULT);
 
   //
-  // LCD Backlight Timeout
+  // LCD Backlight / Sleep Timeout
   //
   #if LCD_BACKLIGHT_TIMEOUT
     ui.lcd_backlight_timeout = LCD_BACKLIGHT_TIMEOUT;

buildroot/share/PlatformIO/scripts/common-dependencies.h

   #define HAS_SAVED_POSITIONS
 #endif
 
-#if ENABLED(HOST_PROMPT_SUPPORT) && DISABLED(EMERGENCY_PARSER)
-  #define HAS_GCODE_M876
-#endif
-
 #if ENABLED(DUET_SMART_EFFECTOR) && PIN_EXISTS(SMART_EFFECTOR_MOD)
   #define HAS_SMART_EFF_MOD
 #endif

platformio.ini

   -<src/gcode/lcd/M0_M1.cpp>
   -<src/gcode/lcd/M73.cpp>
   -<src/gcode/lcd/M117.cpp>
-  -<src/gcode/lcd/M250.cpp> -<src/gcode/lcd/M256.cpp>
+  -<src/gcode/lcd/M250.cpp> -<src/gcode/lcd/M255.cpp> -<src/gcode/lcd/M256.cpp>
   -<src/gcode/lcd/M300.cpp>
   -<src/gcode/lcd/M414.cpp>
   -<src/gcode/lcd/M995.cpp>