receiver: add option to not wait for a reply when requesting to device

lib/logitech_receiver/base.py

@@ -312,16 +312,14 @@ del namedtuple
 #
 
 
-def request(handle, devnumber, request_id, *params):
+# a very few requests (e.g., host switching) do not expect a reply, but use no_reply=True with extreme caution
+def request(handle, devnumber, request_id, *params, no_reply=False):
     """Makes a feature call to a device and waits for a matching reply.
-
-    This function will wait for a matching reply indefinitely.
-
     :param handle: an open UR handle.
     :param devnumber: attached device number.
     :param request_id: a 16-bit integer.
     :param params: parameters for the feature call, 3 to 16 bytes.
-    :returns: the reply data, or ``None`` if some error occurred.
+    :returns: the reply data, or ``None`` if some error occurred. or no reply expected
     """
 
     # import inspect as _inspect
@@ -354,6 +352,9 @@ def request(handle, devnumber, request_id, *params):
     _skip_incoming(handle, ihandle, notifications_hook)
     write(ihandle, devnumber, request_data)
 
+    if no_reply:
+        return None
+
     # we consider timeout from this point
     request_started = _timestamp()
     delta = 0

lib/logitech_receiver/hidpp20.py

@@ -435,11 +435,11 @@ class KeysArray(object):
 #
 
 
-def feature_request(device, feature, function=0x00, *params):
+def feature_request(device, feature, function=0x00, *params, no_reply=False):
     if device.online and device.features:
         if feature in device.features:
             feature_index = device.features.index(int(feature))
-            return device.request((feature_index << 8) + (function & 0xFF), *params)
+            return device.request((feature_index << 8) + (function & 0xFF), *params, no_reply=no_reply)
 
 
 def get_firmware(device):

lib/logitech_receiver/receiver.py

@@ -284,15 +284,15 @@ class PairedDevice(object):
             _log.info('%s: device notifications %s %s', self, 'enabled' if enable else 'disabled', flag_names)
         return flag_bits if ok else None
 
-    def request(self, request_id, *params):
-        return _base.request(self.receiver.handle, self.number, request_id, *params)
+    def request(self, request_id, *params, no_reply=False):
+        return _base.request(self.receiver.handle, self.number, request_id, *params, no_reply=no_reply)
 
     read_register = _hidpp10.read_register
     write_register = _hidpp10.write_register
 
-    def feature_request(self, feature, function=0x00, *params):
+    def feature_request(self, feature, function=0x00, *params, no_reply=False):
         if self.protocol >= 2.0:
-            return _hidpp20.feature_request(self, feature, function, *params)
+            return _hidpp20.feature_request(self, feature, function, *params, no_reply=no_reply)
 
     def ping(self):
         """Checks if the device is online, returns True of False"""