Makes BGFLUSH_EXTRA_TIME configurable (#176)

* Makes BGFLUSH_EXTRA_TIME configurable

* Remove dockable probe PR refs

* Add test and missing dot

docs/Config_Reference.md

@@ -119,6 +119,10 @@ A collection of DangerKlipper-specific system options
 #   When set to true, SAVE_CONFIG will recursively read [include ...] blocks
 #   for conflicts to autosave data. Any configurations updated will be backed
 #   up to configs/config_backups.
+#bgflush_extra_time: 0.250
+#   This allows to set extra flush time (in seconds). Under certain conditions, 
+#   a low value will result in an error if message is not get flushed, a high value
+#   (0.250) will result in homing/probing latency. The default is 0.250
 ```
 
 ## Common kinematic settings

klippy/extras/danger_options.py

@@ -25,6 +25,10 @@ def __init__(self, config):
         self.adc_ignore_limits = config.getboolean("adc_ignore_limits", False)
         self.autosave_includes = config.getboolean("autosave_includes", False)
 
+        self.bgflush_extra_time = config.getfloat(
+            "bgflush_extra_time", 0.250, minval=0.0
+        )
+
 
 def load_config(config):
     return DangerOptions(config)

klippy/toolhead.py

@@ -230,7 +230,6 @@ def add_move(self, move):
 BUFFER_TIME_START = 0.250
 BGFLUSH_LOW_TIME = 0.200
 BGFLUSH_BATCH_TIME = 0.200
-BGFLUSH_EXTRA_TIME = 0.250
 MIN_KIN_TIME = 0.100
 MOVE_BATCH_TIME = 0.500
 STEPCOMPRESS_FLUSH_TIME = 0.050
@@ -249,6 +248,7 @@ class DripModeEndSignal(Exception):
 class ToolHead:
     def __init__(self, config):
         self.printer = config.get_printer()
+        self.danger_options = self.printer.lookup_object("danger_options")
         self.reactor = self.printer.get_reactor()
         self.all_mcus = [
             m for n, m in self.printer.lookup_objects(module="mcu")
@@ -533,7 +533,10 @@ def _flush_handler(self, eventtime):
                     self.check_stall_time = self.print_time
             # In "NeedPrime"/"Priming" state - flush queues if needed
             while 1:
-                end_flush = self.need_flush_time + BGFLUSH_EXTRA_TIME
+                end_flush = (
+                    self.need_flush_time
+                    + self.danger_options.bgflush_extra_time
+                )
                 if self.last_flush_time >= end_flush:
                     self.do_kick_flush_timer = True
                     return self.reactor.NEVER

test/klippy/danger_options.cfg

@@ -10,6 +10,7 @@ allow_plugin_override: True
 multi_mcu_trsync_timeout: 0.05
 adc_ignore_limits: True
 autosave_includes: True
+bgflush_extra_time: 0.250
 
 [stepper_x]
 step_pin: PF0