Ignore disconnect callbacks before first successful connection by eputtone · Pull Request #119 · Jakeler/ble-serial

eputtone · 2026-04-04T09:18:34Z

Description

On Linux/BlueZ, disconnect callbacks can occur during failed connection attempts before a stable connection is established.

Currently, these callbacks call stop_loop() unconditionally. That can cause the application to shut down prematurely even if a subsequent connection attempt succeeds.

This change ignores disconnect callbacks until after the first successful connection has completed, while preserving the existing behavior for disconnects after connection.

Example

Raspberry Pi 3+ / Broadcom chip (BCM4345C0) / Raspberry Pi OS Lite 13 when running ble_serial over Wifi + SSH. The problem does not occur when using cable connection.

Before the suggested change:

# python -m ble_serial -v -t 30 -d XX:XX:XX:XX:XX:XX
11:58:40.609 | DEBUG | main.py: Running: Namespace(verbose=1, timeout=30.0, adapter='hci0', mtu=20, gap_role='client', gap_name=None, device='XX:XX:XX:XX:XX:XX', addr_type='public', service_uuid=None, read_uuid=None, write_uuid=None, mode='rw', write_with_response=False, filename=None, binlog=False, port='/tmp/ttyBLE', tcp_host='127.0.0.1', tcp_port=None)
11:58:40.610 | DEBUG | selector_events.py: Using selector: EpollSelector
11:58:40.612 | INFO | linux_pty.py: Port endpoint created on /tmp/ttyBLE -> /dev/pts/1
11:58:40.612 | INFO | ble_client.py: Receiver set up
11:58:40.802 | INFO | ble_client.py: Trying to connect with XX:XX:XX:XX:XX:XX: 12150AF00399
11:58:41.910 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:41.911 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:42.509 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:42.509 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:43.489 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:43.489 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:44.280 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:44.281 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:45.040 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:45.040 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:45.759 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:45.759 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:46.510 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:46.511 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:47.299 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:47.299 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:48.070 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:48.071 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:49.020 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:49.021 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:50.110 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:50.111 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:51.199 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:51.199 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:52.000 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:52.001 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:52.720 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:52.721 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:54.873 | INFO | ble_client.py: Device XX:XX:XX:XX:XX:XX connected
11:58:54.875 | DEBUG | ble_client.py: No write-without-response uuid specified, trying builtin list
11:58:54.877 | DEBUG | ble_client.py: Characteristic candidates for write-without-response: 
	0000ff02-0000-1000-8000-00805f9b34fb (Handle: 20): Vendor specific ['read', 'write-without-response']
	0000ff01-0000-1000-8000-00805f9b34fb (Handle: 16): Vendor specific ['read', 'notify']
11:58:54.879 | INFO | ble_client.py: Found write-without-response characteristic 0000ff02-0000-1000-8000-00805f9b34fb (H. 20)
11:58:54.880 | DEBUG | ble_client.py: No notify uuid specified, trying builtin list
11:58:54.881 | DEBUG | ble_client.py: Characteristic candidates for notify: 
	0000ff02-0000-1000-8000-00805f9b34fb (Handle: 20): Vendor specific ['read', 'write-without-response']
	0000ff01-0000-1000-8000-00805f9b34fb (Handle: 16): Vendor specific ['read', 'notify']
11:58:54.883 | INFO | ble_client.py: Found notify characteristic 0000ff01-0000-1000-8000-00805f9b34fb (H. 16)
11:58:55.092 | INFO | main.py: Running main loop!
11:58:55.094 | DEBUG | main.py: Completed Tasks: [(<coroutine object BLE_client.send_loop at 0x75666e98>, None)]
11:58:55.095 | DEBUG | main.py: Pending Tasks: [<coroutine object BLE_client.check_loop at 0x757829e8>, <coroutine object UART.run_loop at 0x75666bf8>]
11:58:55.096 | WARNING | main.py: Shutdown initiated
11:58:55.096 | INFO | linux_pty.py: Serial reader and symlink removed
11:58:57.501 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
11:58:57.502 | INFO | ble_client.py: Stopping Bluetooth event loop
11:58:57.504 | INFO | ble_client.py: Bluetooth disconnected
11:58:57.505 | INFO | main.py: Shutdown complete.

With the proposed change:

python -m ble_serial -v -t 30 -d XX:XX:XX:XX:XX:XX
12:01:42.688 | DEBUG | main.py: Running: Namespace(verbose=1, timeout=30.0, adapter='hci0', mtu=20, gap_role='client', gap_name=None, device='XX:XX:XX:XX:XX:XX', addr_type='public', service_uuid=None, read_uuid=None, write_uuid=None, mode='rw', write_with_response=False, filename=None, binlog=False, port='/tmp/ttyBLE', tcp_host='127.0.0.1', tcp_port=None)
12:01:42.689 | DEBUG | selector_events.py: Using selector: EpollSelector
12:01:42.690 | INFO | linux_pty.py: Port endpoint created on /tmp/ttyBLE -> /dev/pts/1
12:01:42.691 | INFO | ble_client.py: Receiver set up
12:01:42.905 | INFO | ble_client.py: Trying to connect with XX:XX:XX:XX:XX:XX: 12150AF00399
12:01:43.430 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:43.430 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:44.160 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:44.160 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:44.922 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:44.922 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:45.742 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:45.742 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:46.710 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:46.711 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:47.539 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:47.539 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:48.119 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:48.119 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:49.770 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:49.771 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:50.580 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:50.581 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:51.380 | WARNING | ble_client.py: Device XX:XX:XX:XX:XX:XX disconnected
12:01:51.381 | DEBUG | ble_client.py: Ignoring pre-connect disconnect callback
12:01:53.694 | INFO | ble_client.py: Device XX:XX:XX:XX:XX:XX connected
12:01:53.695 | DEBUG | ble_client.py: No write-without-response uuid specified, trying builtin list
12:01:53.695 | DEBUG | ble_client.py: Characteristic candidates for write-without-response: 
	0000ff02-0000-1000-8000-00805f9b34fb (Handle: 20): Vendor specific ['read', 'write-without-response']
	0000ff01-0000-1000-8000-00805f9b34fb (Handle: 16): Vendor specific ['read', 'notify']
12:01:53.696 | INFO | ble_client.py: Found write-without-response characteristic 0000ff02-0000-1000-8000-00805f9b34fb (H. 20)
12:01:53.697 | DEBUG | ble_client.py: No notify uuid specified, trying builtin list
12:01:53.697 | DEBUG | ble_client.py: Characteristic candidates for notify: 
	0000ff02-0000-1000-8000-00805f9b34fb (Handle: 20): Vendor specific ['read', 'write-without-response']
	0000ff01-0000-1000-8000-00805f9b34fb (Handle: 16): Vendor specific ['read', 'notify']
12:01:53.699 | INFO | ble_client.py: Found notify characteristic 0000ff01-0000-1000-8000-00805f9b34fb (H. 16)
12:01:53.920 | INFO | main.py: Running main loop!

Related btmon log. Due to radio interference from WIFI or poor coordination between BlueZ + brcmfmac, establishing the connection fails at Connection Failed to be Established (0x3e). But with large enough timeout, connection will eventually succeed.

< HCI Command: LE Create Connection (0x08|0x000d) plen 25                                                              #19 [hci0] 7.677274
        Scan interval: 60.000 msec (0x0060)
        Scan window: 60.000 msec (0x0060)
        Filter policy: Accept list is not used (0x00)
        Peer address type: Public (0x00)
        Peer address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Own address type: Public (0x00)
        Min connection interval: 25.00 msec (0x0014)
        Max connection interval: 50.00 msec (0x0028)
        Connection latency: 0 (0x0000)
        Supervision timeout: 10000 msec (0x03e8)
        Min connection length: 0.000 msec (0x0000)
        Max connection length: 0.000 msec (0x0000)
> HCI Event: Command Status (0x0f) plen 4                                                                              #20 [hci0] 7.677809
      LE Create Connection (0x08|0x000d) ncmd 1
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 19                                                                              #21 [hci0] 7.864809
      LE Connection Complete (0x01)
        Status: Success (0x00)
        Handle: 64
        Role: Central (0x00)
        Peer address type: Public (0x00)
        Peer address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Connection interval: 48.75 msec (0x0027)
        Connection latency: 0 (0x0000)
        Supervision timeout: 10000 msec (0x03e8)
        Central clock accuracy: 0x00
@ MGMT Event: Device Connected (0x000b) plen 34                                                                   {0x0001} [hci0] 7.864855
        LE Address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Flags: 0x00000008
          Connection Locally Initiated
        Data length: 21
        Flags: 0x06
          LE General Discoverable Mode
          BR/EDR Not Supported
        16-bit Service UUIDs (partial): 1 entry
          Unknown (0xff00)
        Name (complete): 12150AF00399
btmon[1587]: @ RAW Open: btmon (privileged) version 2.22                                                                 {0x0002} 7.866041
btmon[1587]: @ RAW Close: btmon                                                                                          {0x0002} 7.866059
< HCI Command: LE Read Remote Used Features (0x08|0x0016) plen 2                                                       #22 [hci0] 7.922815
        Handle: 64 Address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
> HCI Event: Command Status (0x0f) plen 4                                                                              #23 [hci0] 7.923126
      LE Read Remote Used Features (0x08|0x0016) ncmd 1
        Status: Success (0x00)
> HCI Event: LE Meta Event (0x3e) plen 12                                                                              #24 [hci0] 8.179215
      LE Read Remote Used Features (0x04)
        Status: Connection Failed to be Established (0x3e)
        Handle: 64 Address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Features: 0x3f 0x00 0x00 0x08 0x00 0x00 0x00 0x00
          LE Encryption
          Connection Parameter Request Procedure
          Extended Reject Indication
          Peripheral-initiated Features Exchange
          LE Ping
          LE Data Packet Length Extension
          Remote Public Key Validation
> HCI Event: Disconnect Complete (0x05) plen 4                                                                         #25 [hci0] 8.179840
        Status: Success (0x00)
        Handle: 64 Address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Reason: Connection Failed to be Established (0x3e)
@ MGMT Event: Device Disconnected (0x000c) plen 8                                                                 {0x0001} [hci0] 8.232864
        LE Address: XX:XX:XX:XX:XX:XX (Iton Technology Corp.)
        Reason: Unspecified (0x00)

Ignore disconnect callbacks before first successful connection

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Ignore disconnect callbacks before first successful connection#119

Ignore disconnect callbacks before first successful connection#119
eputtone wants to merge 1 commit into
Jakeler:mainfrom
eputtone:fix/pi-disconnect-shutdown

eputtone commented Apr 4, 2026

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eputtone commented Apr 4, 2026

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