From 2fbaa4a3aac95fc6a9e2e737043cfdade7f7382c Mon Sep 17 00:00:00 2001
From: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Date: Sun, 14 Aug 2022 20:26:48 -0400
Subject: [PATCH] receiver: return null values if no pairing information
 available

---
 lib/logitech_receiver/device.py   |  2 +-
 lib/logitech_receiver/receiver.py | 16 +++++++---------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/lib/logitech_receiver/device.py b/lib/logitech_receiver/device.py
index c4a5f45f..4820ac1e 100644
--- a/lib/logitech_receiver/device.py
+++ b/lib/logitech_receiver/device.py
@@ -227,7 +227,7 @@ class Device:
         return self._tid_map
 
     def update_pairing_information(self):
-        if self.receiver:
+        if self.receiver and (not self.wpid or self._kind is None or self._polling_rate is None):
             wpid, kind, polling_rate = self.receiver.device_pairing_information(self.number)
             if not self.wpid:
                 self.wpid = wpid
diff --git a/lib/logitech_receiver/receiver.py b/lib/logitech_receiver/receiver.py
index 2bd7be78..39951872 100644
--- a/lib/logitech_receiver/receiver.py
+++ b/lib/logitech_receiver/receiver.py
@@ -171,8 +171,10 @@ class Receiver:
                 return wpid, kind, 0
             else:
                 raise _base.NoSuchDevice(number=n, receiver=self, error='read Bolt wpid')
+        wpid = 0
+        kind = None
+        polling_rate = None
         pair_info = self.read_register(_R.receiver_info, _IR.pairing_information + n - 1)
-        polling_rate = 0
         if pair_info:  # may be either a Unifying receiver, or an Unifying-ready receiver
             wpid = _strhex(pair_info[3:5])
             kind = _hidpp10.DEVICE_KIND[ord(pair_info[7:8]) & 0x0F]
@@ -183,14 +185,11 @@ class Receiver:
                 _log.error('Unable to get wpid from udev for device %d of %s', n, self)
                 raise _base.NoSuchDevice(number=n, receiver=self, error='Not present 27Mhz device')
             kind = _hidpp10.DEVICE_KIND[self.get_kind_from_index(n, self)]
-        else:
-            # unifying protocol not supported, probably an old Nano receiver
+        else:  # unifying protocol not supported, may be an old Nano receiver
             device_info = self.read_register(_R.receiver_info, 0x04)
-            if device_info is None:
-                _log.error('failed to read Nano wpid for device %d of %s', n, self)
-                raise _base.NoSuchDevice(number=n, receiver=self, error='read Nano wpid')
-            wpid = _strhex(device_info[3:5])
-            kind = _hidpp10.DEVICE_KIND[0x00]  # unknown kind
+            if device_info:
+                wpid = _strhex(device_info[3:5])
+                kind = _hidpp10.DEVICE_KIND[0x00]  # unknown kind
         return wpid, kind, polling_rate
 
     def device_extended_pairing_information(self, n):
@@ -246,7 +245,6 @@ class Receiver:
 
         try:
             dev = Device(self, number, notification)
-            assert dev.wpid
             if _log.isEnabledFor(_INFO):
                 _log.info('%s: found new device %d (%s)', self, number, dev.wpid)
             self._devices[number] = dev