receiver: only check for device features once per device

lib/logitech_receiver/receiver.py

@@ -71,6 +71,7 @@ class PairedDevice(object):
 		self._keys = None
 		self._registers = None
 		self._settings = None
+		self._feature_settings_checked = False
 
 		# Misc stuff that's irrelevant to any functionality, but may be
 		# displayed in the UI and caching it here helps.
@@ -251,8 +252,8 @@ class PairedDevice(object):
 				self._settings = [s(self) for s in self.descriptor.settings]
 			else:
 				self._settings = []
-
-		_check_feature_settings(self, self._settings)
+		if not self._feature_settings_checked:
+			self._feature_settings_checked =_check_feature_settings(self, self._settings)
 		return self._settings
 
 	def enable_notifications(self, enable=True):

lib/logitech_receiver/settings_templates.py

@@ -371,12 +371,13 @@ del _SETTINGS_LIST
 #
 #
 
+# Returns True if device was queried to find features, False otherwise
 def check_feature_settings(device, already_known):
 	"""Try to auto-detect device settings by the HID++ 2.0 features they have."""
 	if device.features is None or not device.online:
-		return
+		return False
 	if device.protocol and device.protocol < 2.0:
-		return
+		return False
 
 	def check_feature(name, featureId, field_name=None):
 		"""
@@ -414,3 +415,4 @@ def check_feature_settings(device, already_known):
 	check_feature(_POINTER_SPEED[0], _F.POINTER_SPEED)
 	check_feature(_SMART_SHIFT[0],   _F.SMART_SHIFT)
 	check_feature(_BACKLIGHT[0],   	 _F.BACKLIGHT2)
+	return True