Merge pull request #461 from canton7/bugfix/serial-select

Use PosixPollSerial from pyserial for serial connections where possible

custom_components/foxess_modbus/modbus_client.py

@@ -1,6 +1,7 @@
 """The client used to talk Modbus"""
 import asyncio
 import logging
+import os
 import select
 import socket
 import time
@@ -178,6 +179,13 @@ def __init__(self, hass: HomeAssistant, protocol: str, adapter: InverterAdapter,
             "delay_on_connect": 1 if adapter.connection_type == LAN else None,
         }
 
+        # If PosixPollSerial is supported, use that. This uses poll rather than select, which means we don't break when
+        # there are more than 1024 fds. See #457.
+        # Only supported on posix, see https://github.com/pyserial/pyserial/blob/7aeea35429d15f3eefed10bbb659674638903e3a/serial/__init__.py#L31
+        if protocol == SERIAL and os.name == "posix":
+            # https://pyserial.readthedocs.io/en/latest/url_handlers.html#alt
+            config["port"] = f"alt://{config['port']}?class=PosixPollSerial"
+
         # Some serial devices need a short delay after polling. Also do this for the inverter, just
         # in case it helps.
         self._poll_delay = 30 / 1000 if protocol == SERIAL or adapter.connection_type == LAN else 0