🚸 G28 / G30 return for failed probe deploy (#25652)

Co-authored-by: Scott Lahteine <[email protected]>

Marlin/src/gcode/calibrate/G28.cpp

@@ -205,6 +205,11 @@
  *  L<bool>   Force leveling state ON (if possible) or OFF after homing (Requires RESTORE_LEVELING_AFTER_G28 or ENABLE_LEVELING_AFTER_G28)
  *  O         Home only if the position is not known and trusted
  *  R<linear> Raise by n mm/inches before homing
+ *  H         Hold the current X/Y position when executing a home Z, or if
+ *            multiple axes are homed, the position when Z home is executed.
+ *            When using a probe for Z Home, positions close to the edge may
+ *            fail with position unreachable due to probe/nozzle offset.  This
+ *            can be used to avoid a model.
  *
  * Cartesian/SCARA parameters
  *
@@ -461,7 +466,12 @@ void GcodeSuite::G28() {
             #endif
 
             #if ENABLED(Z_SAFE_HOMING)
-              if (TERN1(POWER_LOSS_RECOVERY, !parser.seen_test('H'))) home_z_safely(); else homeaxis(Z_AXIS);
+              // H means hold the current X/Y position when probing.
+              // Otherwise move to the define safe X/Y position before homing Z.
+              if (!parser.seen_test('H'))
+                home_z_safely();
+              else
+                homeaxis(Z_AXIS);
             #else
               homeaxis(Z_AXIS);
             #endif

Marlin/src/module/motion.cpp

@@ -2679,8 +2679,12 @@ void prepare_line_to_destination() {
     //
     // Homing Z with a probe? Raise Z (maybe) and deploy the Z probe.
     //
-    if (TERN0(HOMING_Z_WITH_PROBE, axis == Z_AXIS && probe.deploy()))
-      return;
+    #if HOMING_Z_WITH_PROBE
+      if (axis == Z_AXIS && probe.deploy()) {
+        probe.stow();
+        return;
+      }
+    #endif
 
     // Set flags for X, Y, Z motor locking
     #if HAS_EXTRA_ENDSTOPS
@@ -2698,8 +2702,16 @@ void prepare_line_to_destination() {
     //
     #if HOMING_Z_WITH_PROBE
       if (axis == Z_AXIS) {
-        if (TERN0(BLTOUCH, bltouch.deploy())) return;   // BLTouch was deployed above, but get the alarm state.
-        if (TERN0(PROBE_TARE, probe.tare())) return;
+        #if ENABLED(BLTOUCH)
+          if (bltouch.deploy()) {  // BLTouch was deployed above, but get the alarm state.
+            bltouch.stow();
+            return;
+          }
+        #endif
+        if (TERN0(PROBE_TARE, probe.tare())) {
+          probe.stow();
+          return;
+        }
         TERN_(BD_SENSOR, bdl.config_state = BDS_HOMING_Z);
       }
     #endif
@@ -2781,8 +2793,10 @@ void prepare_line_to_destination() {
       #endif // DETECT_BROKEN_ENDSTOP
 
       #if ALL(HOMING_Z_WITH_PROBE, BLTOUCH)
-        if (axis == Z_AXIS && !bltouch.high_speed_mode && bltouch.deploy())
+        if (axis == Z_AXIS && !bltouch.high_speed_mode && bltouch.deploy()) {
+          bltouch.stow();
           return; // Intermediate DEPLOY (in LOW SPEED MODE)
+        }
       #endif
 
       // Slow move towards endstop until triggered

Marlin/src/module/probe.cpp

@@ -961,11 +961,6 @@ float Probe::probe_at_point(
     DEBUG_POS("", current_position);
   }
 
-  #if ENABLED(BLTOUCH)
-    // Reset a BLTouch in HS mode if already triggered
-    if (bltouch.high_speed_mode && bltouch.triggered()) bltouch._reset();
-  #endif
-
   // Use a safe Z height for the XY move
   const float safe_z = _MAX(current_position.z, z_clearance);
 
@@ -1003,6 +998,13 @@ float Probe::probe_at_point(
 
   #else // !BD_SENSOR
 
+    #if ENABLED(BLTOUCH)
+      // Now at the safe_z if it is still triggered it may be in an alarm
+      // condition.  Reset to clear alarm has a side effect of stowing the probe,
+      // which the following deploy will handle.
+      if (bltouch.triggered()) bltouch._reset();
+    #endif
+
     measured_z = deploy() ? NAN : run_z_probe(sanity_check, z_min_point, z_clearance) + offset.z;
 
     // Deploy succeeded and a successful measurement was done.