Backports from MK3

- Remove attempted recovery from RX buffer full (just drop chars)
  - Use CRITICAL_SECTION in LCD menu sync
  - Remove M851 command and zprobe_zoffset (Use live-Z instead)

Firmware/Configuration.h

@@ -10,7 +10,7 @@
 
 // Firmware version
 #define FW_version "3.1.0"
-#define FW_local_variant 5
+#define FW_local_variant 6
 #define FW_report_version FW_version " r" STR(FW_local_variant)
 
 #define FW_PRUSA3D_MAGIC "PRUSA3DFW"
@@ -467,7 +467,7 @@ const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of
 //===========================================================================
 
 // Custom M code points
-#define CUSTOM_M_CODES
+//#define CUSTOM_M_CODES
 #ifdef CUSTOM_M_CODES
   #define CUSTOM_M_CODE_SET_Z_PROBE_OFFSET 851
   #define Z_PROBE_OFFSET_RANGE_MIN -15

Firmware/Marlin_main.cpp

@@ -1199,8 +1199,7 @@ void setup()
 	card.initsd();
 
 	if (eeprom_read_dword((uint32_t*)(EEPROM_TOP - 4)) == 0x0ffffffff &&
-		eeprom_read_dword((uint32_t*)(EEPROM_TOP - 8)) == 0x0ffffffff &&
-		eeprom_read_dword((uint32_t*)(EEPROM_TOP - 12)) == 0x0ffffffff) {
+	    eeprom_read_dword((uint32_t*)(EEPROM_TOP - 8)) == 0x0ffffffff) {
 		// Maiden startup. The firmware has been loaded and first started on a virgin RAMBo board,
 		// where all the EEPROM entries are set to 0x0ff.
 		// Once a firmware boots up, it forces at least a language selection, which changes
@@ -1468,21 +1467,12 @@ void get_command()
 	if (!cmdqueue_could_enqueue_back(MAX_CMD_SIZE - 1)) 
 		return;
 	
-	bool rx_buffer_full = false; //flag that serial rx buffer is full
-
   while (MYSERIAL.available() > 0) {
-	  if (MYSERIAL.available() == RX_BUFFER_SIZE - 1) { //compare number of chars buffered in rx buffer with rx buffer size
-		  SERIAL_ECHOLNPGM("Full RX Buffer");   //if buffer was full, there is danger that reading of last gcode will not be completed
-		  rx_buffer_full = true;				//sets flag that buffer was full	
-	  }
+
     char serial_char = MYSERIAL.read();
-    if (selectedSerialPort == 1) {
-        selectedSerialPort = 0;
-        MYSERIAL.write(serial_char);
-        selectedSerialPort = 1;
-    }
-      TimeSent = millis();
-      TimeNow = millis();
+
+    TimeSent = millis();
+    TimeNow = millis();
 
     if (serial_char < 0)
         // Ignore extended ASCII characters. These characters have no meaning in the G-code apart from the file names
@@ -1636,13 +1626,6 @@ void get_command()
         }
     }
 
-	//add comment
-	if (rx_buffer_full == true && serial_count > 0) {   //if rx buffer was full and string was not properly terminated
-		rx_buffer_full = false;
-		bufindw = bufindw - serial_count;				//adjust tail of the buffer to prepare buffer for writing new command
-		serial_count = 0;
-	}
-
   #ifdef SDSUPPORT
   if(!card.sdprinting || serial_count!=0){
     // If there is a half filled buffer from serial line, wait until return before
@@ -5559,8 +5542,7 @@ case 404:  //M404 Enter the nominal filament width (3mm, 1.75mm ) N<3.0> or disp
         {
           zprobe_zoffset = -value; // compare w/ line 278 of ConfigurationStore.cpp
           SERIAL_ECHO_START;
-          SERIAL_ECHOLNRPGM(CAT4(MSG_ZPROBE_ZOFFSET, " ", MSG_OK,PSTR("")));
-          SERIAL_PROTOCOLLN("");
+          SERIAL_ECHOLN(CAT4(MSG_ZPROBE_ZOFFSET, " ", MSG_OK,PSTR("")));
         }
         else
         {
@@ -5576,7 +5558,7 @@ case 404:  //M404 Enter the nominal filament width (3mm, 1.75mm ) N<3.0> or disp
       else
       {
           SERIAL_ECHO_START;
-          SERIAL_ECHOLNRPGM(CAT2(MSG_ZPROBE_ZOFFSET, PSTR(" : ")));
+          SERIAL_ECHO(CAT2(MSG_ZPROBE_ZOFFSET, PSTR(" : ")));
           SERIAL_ECHO(-zprobe_zoffset);
           SERIAL_PROTOCOLLN("");
       }

Firmware/language_all.cpp

@@ -3077,7 +3077,7 @@ const char * const MSG_SILENT_MODE_ON_LANG_TABLE[LANG_NUM] PROGMEM = {
 	MSG_SILENT_MODE_ON_DE
 };
 
-const char MSG_SKEW_CORRECTION_EN[] PROGMEM = "Very small XY skew. Disable skew correction?";
+const char MSG_SKEW_CORRECTION_EN[] PROGMEM = "Very little skew detected. Disable correction?";
 const char * const MSG_SKEW_CORRECTION_LANG_TABLE[1] PROGMEM = {
 	MSG_SKEW_CORRECTION_EN
 };

Firmware/ultralcd.cpp

@@ -364,10 +364,13 @@ uint8_t lcdDrawUpdate = 2;                  /* Set to none-zero when the LCD nee
 // float raw_Ki, raw_Kd;
 #endif
 
-static void lcd_goto_menu(menuFunc_t menu, const uint32_t encoder = 0, const bool feedback = true, bool reset_menu_state = true) {
+static void lcd_goto_menu(menuFunc_t menu, const uint32_t encoder = 0, const bool feedback = true, bool reset_menu_state = true)
+{
+  CRITICAL_SECTION_START
   if (currentMenu != menu) {
     currentMenu = menu;
     encoderPosition = encoder;
+    CRITICAL_SECTION_END
     if (reset_menu_state) {
         // Resets the global shared C union.
         // This ensures, that the menu entered will find out, that it shall initialize itself.
@@ -379,6 +382,8 @@ static void lcd_goto_menu(menuFunc_t menu, const uint32_t encoder = 0, const boo
 #if defined(LCD_PROGRESS_BAR) && defined(SDSUPPORT)
     lcd_set_custom_characters(menu == lcd_status_screen);
 #endif
+  } else {
+    CRITICAL_SECTION_END
   }
 }
 
@@ -5189,8 +5194,10 @@ void lcd_sdcard_menu()
   } \
   static void menu_action_setting_edit_ ## _name (const char* pstr, _type* ptr, _type minValue, _type maxValue) \
   { \
+    CRITICAL_SECTION_START \
     menuData.editMenuParentState.prevMenu = currentMenu; \
     menuData.editMenuParentState.prevEncoderPosition = encoderPosition; \
+    CRITICAL_SECTION_END \
     \
     lcdDrawUpdate = 2; \
     menuData.editMenuParentState.editLabel = pstr; \

platformio.ini

@@ -21,7 +21,7 @@
 [platformio]
 src_dir		= ./Firmware
 lib_dir		= /opt/arduino-1.8.5/libraries
-envs_dir	= ./pbuild
+build_dir	= ./pbuild
 env_default	= Prusa3D
 
 [env:Prusa3D]