From fe55e39560ba493e21f94dfeedcaf38687a554ae Mon Sep 17 00:00:00 2001
From: effective-light <someguy@effective-light.com>
Date: Tue, 11 Aug 2020 17:00:14 -0400
Subject: [PATCH] udev: use HID_PHYS instead of HID_UNIQ to look for relevant
 child nodes

---
 lib/hidapi/__init__.py            |  1 +
 lib/hidapi/udev.py                | 12 ++++++++++++
 lib/logitech_receiver/device.py   | 10 ++--------
 lib/logitech_receiver/receiver.py |  1 +
 4 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/lib/hidapi/__init__.py b/lib/hidapi/__init__.py
index 8e55b436..4202b676 100644
--- a/lib/hidapi/__init__.py
+++ b/lib/hidapi/__init__.py
@@ -22,6 +22,7 @@ from __future__ import absolute_import, division, print_function, unicode_litera
 
 from hidapi.udev import close  # noqa: F401
 from hidapi.udev import enumerate  # noqa: F401
+from hidapi.udev import find_paired_node  # noqa: F401
 from hidapi.udev import get_manufacturer  # noqa: F401
 from hidapi.udev import get_product  # noqa: F401
 from hidapi.udev import get_serial  # noqa: F401
diff --git a/lib/hidapi/udev.py b/lib/hidapi/udev.py
index 1d8c86ed..cef9d6ea 100644
--- a/lib/hidapi/udev.py
+++ b/lib/hidapi/udev.py
@@ -48,6 +48,7 @@ DeviceInfo = namedtuple(
         'vendor_id',
         'product_id',
         'serial',
+        'phys',
         'release',
         'manufacturer',
         'product',
@@ -127,6 +128,7 @@ def _match(action, device, filter):
             path=device.device_node,
             vendor_id=vid[-4:],
             product_id=pid[-4:],
+            phys=hid_device.get('HID_PHYS'),
             serial=hid_device.get('HID_UNIQ'),
             release=attrs.get('bcdDevice'),
             manufacturer=attrs.get('manufacturer'),
@@ -143,6 +145,7 @@ def _match(action, device, filter):
             path=device.device_node,
             vendor_id=vid[-4:],
             product_id=pid[-4:],
+            phys=None,
             serial=None,
             release=None,
             manufacturer=None,
@@ -153,6 +156,15 @@ def _match(action, device, filter):
         return d_info
 
 
+def find_paired_node(receiver_phys, index):
+    for dev in _Context().list_devices(subsystem='hidraw'):
+        phys = dev.find_parent('hid').get('HID_PHYS')
+        if phys and '{}:{}'.format(receiver_phys, index) == phys:
+            return dev.device_node
+
+    return None
+
+
 def monitor_glib(callback, *device_filters):
     from gi.repository import GLib
 
diff --git a/lib/logitech_receiver/device.py b/lib/logitech_receiver/device.py
index 8abe76da..b1cd0d21 100644
--- a/lib/logitech_receiver/device.py
+++ b/lib/logitech_receiver/device.py
@@ -128,14 +128,8 @@ class Device(object):
             # device is unpaired
             assert self.wpid is not None, 'failed to read wpid: device %d of %s' % (number, receiver)
 
-            for dev in _hid.enumerate({'vendor_id': 0x046d, 'product_id': int(self.receiver.product_id, 16)}):
-                if dev.serial:
-                    split = dev.serial.split('-')
-                    hidraw_serial = ''.join(split[1:]).upper()
-                    if self.serial == hidraw_serial and split[0] == self.wpid:
-                        self.path = dev.path
-                        self.handle = _hid.open_path(dev.path)
-                        break
+            self.path = _hid.find_paired_node(receiver.phys, number)
+            self.handle = _hid.open_path(self.path) if self.path else None
 
             self.descriptor = _DESCRIPTORS.get(self.wpid)
             if self.descriptor is None:
diff --git a/lib/logitech_receiver/receiver.py b/lib/logitech_receiver/receiver.py
index 4db61af2..daa950ae 100644
--- a/lib/logitech_receiver/receiver.py
+++ b/lib/logitech_receiver/receiver.py
@@ -53,6 +53,7 @@ class Receiver(object):
         self.handle = handle
         assert device_info
         self.path = device_info.path
+        self.phys = device_info.phys
         # USB product id, used for some Nano receivers
         self.product_id = device_info.product_id
         product_info = _product_information(self.product_id)