Move last bootscreen delay to end of setup (#21665)

Marlin/src/lcd/HD44780/marlinui_HD44780.cpp

@@ -486,7 +486,9 @@ void MarlinUI::clear_lcd() { lcd.clear(); }
         CENTER_OR_SCROLL(STRING_SPLASH_LINE3, 1500);
       #endif
     }
+  }
 
+  void MarlinUI::bootscreen_completion(const millis_t) {
     lcd.clear();
     safe_delay(100);
     set_custom_characters(CHARSET_INFO);

Marlin/src/lcd/TFTGLCD/marlinui_TFTGLCD.cpp

@@ -397,7 +397,10 @@ static void center_text_P(PGM_P pstart, uint8_t y) {
     center_text_P(PSTR(MARLIN_WEBSITE_URL), 4);
     picBits = ICON_LOGO;
     lcd.print_screen();
-    safe_delay(1500);
+  }
+
+  void MarlinUI::bootscreen_completion(const millis_t sofar) {
+    if ((BOOTSCREEN_TIMEOUT) > sofar) safe_delay((BOOTSCREEN_TIMEOUT) - sofar);
   }
 
 #endif // SHOW_BOOTSCREEN

Marlin/src/lcd/dogm/marlinui_DOGM.cpp

@@ -160,20 +160,21 @@ bool MarlinUI::detected() { return true; }
           #endif
           u8g.firstPage();
           do { draw_custom_bootscreen(f); } while (u8g.nextPage());
-          if (frame_time) safe_delay(frame_time);
+          if (frame_time) early_safe_delay(frame_time);
         }
 
       #ifndef CUSTOM_BOOTSCREEN_TIMEOUT
         #define CUSTOM_BOOTSCREEN_TIMEOUT 2500
       #endif
       #if CUSTOM_BOOTSCREEN_TIMEOUT
-        safe_delay(CUSTOM_BOOTSCREEN_TIMEOUT);
+        early_safe_delay(CUSTOM_BOOTSCREEN_TIMEOUT);
       #endif
     }
   #endif // SHOW_CUSTOM_BOOTSCREEN
 
   // Two-part needed to display all info
   constexpr bool two_part = ((LCD_PIXEL_HEIGHT) - (START_BMPHEIGHT)) < ((MENU_FONT_ASCENT) * 2);
+  constexpr uint8_t bootscreen_pages = 1 + two_part;
 
   // Draw the static Marlin bootscreen from a u8g loop
   // or the animated boot screen within its own u8g loop
@@ -225,17 +226,16 @@ bool MarlinUI::detected() { return true; }
       constexpr millis_t frame_time = MARLIN_BOOTSCREEN_FRAME_TIME;
       LOOP_L_N(f, COUNT(marlin_bootscreen_animation)) {
         draw_bootscreen_bmp((uint8_t*)pgm_read_ptr(&marlin_bootscreen_animation[f]));
-        if (frame_time) safe_delay(frame_time);
+        if (frame_time) early_safe_delay(frame_time);
       }
     #endif
   }
 
   // Show the Marlin bootscreen, with the u8g loop and delays
   void MarlinUI::show_marlin_bootscreen() {
-    constexpr uint8_t pages = two_part ? 2 : 1;
-    for (uint8_t q = pages; q--;) {
+    for (uint8_t q = bootscreen_pages; q--;) {
       draw_marlin_bootscreen(q == 0);
-      safe_delay((BOOTSCREEN_TIMEOUT) / pages);
+      if (q) early_safe_delay((BOOTSCREEN_TIMEOUT) / bootscreen_pages);
     }
   }
 
@@ -244,6 +244,10 @@ bool MarlinUI::detected() { return true; }
     show_marlin_bootscreen();
   }
 
+  void MarlinUI::bootscreen_completion(const millis_t sofar) {
+    if ((BOOTSCREEN_TIMEOUT) / bootscreen_pages > sofar) safe_delay((BOOTSCREEN_TIMEOUT) / bootscreen_pages - sofar);
+  }
+
 #endif // SHOW_BOOTSCREEN
 
 #if ENABLED(LIGHTWEIGHT_UI)

Marlin/src/lcd/marlinui.h

@@ -337,6 +337,7 @@ public:
         static void draw_marlin_bootscreen(const bool line2=false);
         static void show_marlin_bootscreen();
         static void show_bootscreen();
+        static void bootscreen_completion(const millis_t sofar);
       #endif
 
       #if HAS_MARLINUI_U8GLIB

Marlin/src/lcd/tft/ui_320x240.cpp

@@ -60,6 +60,7 @@ void MarlinUI::tft_idle() {
 }
 
 #if ENABLED(SHOW_BOOTSCREEN)
+
   void MarlinUI::show_bootscreen() {
     tft.queue.reset();
 
@@ -81,9 +82,13 @@ void MarlinUI::tft_idle() {
     #endif
 
     tft.queue.sync();
-    safe_delay(BOOTSCREEN_TIMEOUT);
+  }
+
+  void MarlinUI::bootscreen_completion(const millis_t sofar) {
+    if ((BOOTSCREEN_TIMEOUT) > sofar) safe_delay((BOOTSCREEN_TIMEOUT) - sofar);
     clear_lcd();
   }
+
 #endif
 
 void MarlinUI::draw_kill_screen() {

Marlin/src/lcd/tft/ui_480x320.cpp

@@ -60,6 +60,7 @@ void MarlinUI::tft_idle() {
 }
 
 #if ENABLED(SHOW_BOOTSCREEN)
+
   void MarlinUI::show_bootscreen() {
     tft.queue.reset();
 
@@ -81,9 +82,13 @@ void MarlinUI::tft_idle() {
     #endif
 
     tft.queue.sync();
-    safe_delay(BOOTSCREEN_TIMEOUT);
+  }
+
+  void MarlinUI::bootscreen_completion(const millis_t sofar) {
+    if ((BOOTSCREEN_TIMEOUT) > sofar) safe_delay((BOOTSCREEN_TIMEOUT) - sofar);
     clear_lcd();
   }
+
 #endif
 
 void MarlinUI::draw_kill_screen() {