oh jubilee is sick you can block on signals!!

system/ui/lib/wifi_manager.py

@@ -7,6 +7,11 @@ from collections.abc import Callable
 from dataclasses import dataclass
 from enum import IntEnum
 
+from collections import deque
+from jeepney import DBusAddress, new_method_call
+from jeepney.bus_messages import message_bus, MatchRule
+from jeepney.io.blocking import open_dbus_connection
+
 from openpilot.common.swaglog import cloudlog
 from openpilot.system.ui.lib.networkmanager import (NM, NM_PROPERTIES_IFACE, NM_WIRELESS_IFACE, NM_802_11_AP_SEC_PAIR_WEP40,
                                                     NM_802_11_AP_SEC_PAIR_WEP104, NM_802_11_AP_SEC_GROUP_WEP40,
@@ -109,6 +114,49 @@ class AccessPoint:
     )
 
 
+NM = "org.freedesktop.NetworkManager"
+NM_PATH = "/org/freedesktop/NetworkManager"
+NM_IFACE = "org.freedesktop.NetworkManager"
+PROPS_IFACE = "org.freedesktop.DBus.Properties"
+DEV_IFACE = "org.freedesktop.NetworkManager.Device"
+
+
+def wait_props_changed(device_path: str):
+  conn = open_dbus_connection(bus="SYSTEM")
+  try:
+    # Subscribe to PropertiesChanged on that device
+    rule = MatchRule(
+      type="signal",
+      interface=PROPS_IFACE,
+      member="StateChanged",
+      path=device_path,
+    )
+    rule_props = MatchRule(type="signal", sender=NM, interface=PROPS_IFACE, member="PropertiesChanged", path=device_path)
+    rule_state = MatchRule(type="signal", sender=NM, interface=DEV_IFACE, member="StateChanged", path=device_path)
+    rule.add_arg_condition(0, DEV_IFACE)  # only changes for Device iface
+
+    # Tell the bus we want these signals
+    conn.send_and_get_reply(message_bus.AddMatch(rule_props))
+    conn.send_and_get_reply(message_bus.AddMatch(rule_state))
+
+    # Block until a matching signal arrives
+    while True:
+      msg = conn.receive(timeout=None)
+      print(msg)
+
+    with conn.filter(rule, queue=deque(maxlen=1)) as q:
+      msg = conn.recv_until_filtered(q, timeout=None)
+      iface, changed, invalidated = msg.body  # iface:str, changed:a{sv}, invalidated:as
+      # changed is a dict of {prop_name: Variant(...)} – pull what you need:
+      print('changed', changed)
+      state = changed.get("State")
+      if state is not None:
+        # state.value if you’re wrapping Variants; else plain int depending on your helpers
+        print("New device state:", state)
+  finally:
+    conn.close()
+
+
 class WifiManager:
   def __init__(self):
     self._networks = []  # a network can be comprised of multiple APs