Jannis/ha-xiaoxiang-bms
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Add global BLE lock + faster timeouts for multi-device reliability

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Root cause: 3 BMS devices fighting for 3 ESPHome proxy connection slots
simultaneously, causing 80% timeout failures and 22s+ poll times.

Fixes:
- Add shared asyncio.Lock so only one BMS polls at a time — eliminates
  proxy slot contention entirely
- Pass ble_device_callback to establish_connection so retry attempts
  get a fresh BLEDevice (handles proxy path changes)
- Reduce command timeout 5s -> 3s, retries 3 -> 2 (BMS responds in
  <200ms when connection is clean)
- Reduce establish_connection max_attempts 3 -> 2 (fail fast, retry
  next cycle instead of blocking 25s)
- Fixed poll timeout to 15s (was poll_interval-5=25s)

Expected: polls complete in 2-5s instead of 22s, ~95%+ success rate.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Jannis Christiani
2026-04-12 10:05:54 +02:00
parent 1520ed3c0f
commit dcc528b96a
3 changed files with 65 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files
custom_components/xiaoxiang_bms/__init__.py
+16 -2
View File
@@ -1,6 +1,8 @@
"""Xiaoxiang Smart BMS — Home Assistant integration."""
from __future__ import annotations
import asyncio
from homeassistant.components.bluetooth import (
BluetoothChange,
BluetoothScanningMode,
@@ -22,7 +24,19 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
address = entry.data[CONF_ADDRESS]
poll_interval = entry.options.get(CONF_POLL_INTERVAL, DEFAULT_POLL_INTERVAL)
coordinator = BmsCoordinator(hass, address, poll_interval, name=entry.title)
hass.data.setdefault(DOMAIN, {})
# Shared BLE lock — only one BMS connects at a time to avoid
# ESPHome proxy connection slot exhaustion with multiple devices.
if "_ble_lock" not in hass.data[DOMAIN]:
hass.data[DOMAIN]["_ble_lock"] = asyncio.Lock()
ble_lock = hass.data[DOMAIN]["_ble_lock"]
coordinator = BmsCoordinator(
hass, address, poll_interval,
name=entry.title,
ble_lock=ble_lock,
)
# Keep the coordinator's BLE device reference fresh via advertisement callback.
# This avoids stale transport paths when ESPHome proxies cycle.
@@ -45,7 +59,7 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
await coordinator.async_setup()
await coordinator.async_config_entry_first_refresh()
hass.data.setdefault(DOMAIN, {})[entry.entry_id] = coordinator
hass.data[DOMAIN][entry.entry_id] = coordinator
await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
entry.async_on_unload(entry.add_update_listener(_async_update_listener))
custom_components/xiaoxiang_bms/bluetooth_handler.py
+17 -8
View File
@@ -4,6 +4,7 @@ from __future__ import annotations
import asyncio
import logging
import struct
from collections.abc import Callable
from bleak import BleakError
from bleak.backends.device import BLEDevice
@@ -63,8 +64,9 @@ class BmsBluetoothHandler:
self,
ble_device: BLEDevice,
commands: list[bytes],
timeout: float = 5.0,
retries: int = 3,
timeout: float = 3.0,
retries: int = 2,
ble_device_callback: Callable[[], BLEDevice | None] | None = None,
) -> list[bytes | None]:
"""Connect, send each command in sequence, disconnect.
@@ -79,7 +81,8 @@ class BmsBluetoothHandler:
BleakClientWithServiceCache,
ble_device,
self._address,
max_attempts=3,
max_attempts=2,
ble_device_callback=ble_device_callback,
)
try:
await client.start_notify(RX_CHAR_UUID, self._on_notify)
@@ -166,7 +169,7 @@ class BmsBluetoothHandler:
_LOGGER.warning("BLE write failed (attempt %d/%d): %s",
attempt, retries, exc)
if attempt < retries:
await asyncio.sleep(0.5)
await asyncio.sleep(0.3)
continue
try:
@@ -178,7 +181,7 @@ class BmsBluetoothHandler:
_LOGGER.warning("BMS timeout (cmd=0x%s, attempt %d/%d)",
command.hex(), attempt, retries)
if attempt < retries:
await asyncio.sleep(0.5)
await asyncio.sleep(0.3)
return None
@@ -186,7 +189,12 @@ class BmsBluetoothHandler:
# MOS write command
# ------------------------------------------------------------------
async def write_mos(self, ble_device: BLEDevice, value: int) -> bool:
async def write_mos(
self,
ble_device: BLEDevice,
value: int,
ble_device_callback: Callable[[], BLEDevice | None] | None = None,
) -> bool:
"""Send a MOS control write command and return True on ACK.
Follows the same connect -> send -> disconnect pattern as poll() so
@@ -200,12 +208,13 @@ class BmsBluetoothHandler:
BleakClientWithServiceCache,
ble_device,
self._address,
max_attempts=3,
max_attempts=2,
ble_device_callback=ble_device_callback,
)
try:
await client.start_notify(RX_CHAR_UUID, self._on_notify)
await asyncio.sleep(0.3)
response = await self._request(client, command, timeout=5.0, retries=2)
response = await self._request(client, command, timeout=3.0, retries=2)
return response is not None and response[2] == 0x00
finally:
try:
custom_components/xiaoxiang_bms/coordinator.py
+32 -13
View File
@@ -22,6 +22,11 @@ _LOGGER = logging.getLogger(__name__)
# the last known data instead so the UI doesn't oscillate.
_FAILURES_BEFORE_UNAVAILABLE = 5
# Hard ceiling on the BLE poll operation (connect + commands + disconnect).
# With the global lock preventing contention, connections should be fast —
# 15 s is generous for 2 commands over a local proxy.
_POLL_TIMEOUT = 15
class BmsCoordinator(DataUpdateCoordinator[dict]):
"""Polls the BMS over BLE and distributes data to all sensor entities.
@@ -36,6 +41,7 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
address: str,
poll_interval: int,
name: str = "Xiaoxiang Smart BMS",
ble_lock: asyncio.Lock | None = None,
) -> None:
super().__init__(
hass,
@@ -45,12 +51,14 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
)
self.address = address
self._device_name = name
self._poll_timeout = max(poll_interval - 5, 20)
self._handler = BmsBluetoothHandler(address)
self.hw_version: str | None = None
self._consecutive_failures = 0
# Kept fresh by the BLE advertisement callback registered in __init__.py
self._ble_device: BLEDevice | None = None
# Shared across all BMS coordinator instances so only one BMS connects
# at a time — prevents ESPHome proxy connection slot exhaustion.
self._ble_lock = ble_lock or asyncio.Lock()
# ------------------------------------------------------------------
# Device info — shared by sensor, binary_sensor, number platforms
@@ -82,7 +90,11 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
raise HomeAssistantError(
f"BMS ({self.address}) not reachable — cannot send MOS command"
)
success = await self._handler.write_mos(device, value)
async with self._ble_lock:
success = await self._handler.write_mos(
device, value,
ble_device_callback=self._get_ble_device,
)
if not success:
raise HomeAssistantError("BMS did not acknowledge the MOS command")
await self.async_request_refresh()
@@ -135,17 +147,24 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
if self.hw_version is None:
commands.append(CMD_VERSION)
try:
responses = await asyncio.wait_for(
self._handler.poll(device, commands),
timeout=self._poll_timeout,
)
except asyncio.TimeoutError:
return self._handle_failure(
f"BMS poll timed out after {self._poll_timeout}s"
)
except Exception as exc:
return self._handle_failure(f"BMS poll failed: {exc}")
# Only one BMS polls at a time — prevents proxy connection slot contention.
# The timeout wraps only the actual BLE operation, not the lock wait.
async with self._ble_lock:
try:
responses = await asyncio.wait_for(
self._handler.poll(
device,
commands,
ble_device_callback=self._get_ble_device,
),
timeout=_POLL_TIMEOUT,
)
except asyncio.TimeoutError:
return self._handle_failure(
f"BMS poll timed out after {_POLL_TIMEOUT}s"
)
except Exception as exc:
return self._handle_failure(f"BMS poll failed: {exc}")
general_frame, cell_frame = responses[0], responses[1]