蓝牙设备配对失败：认证问题排查求助

使用bluetoothctl发起DeviceA（配对发起端）与DeviceB的蓝牙配对时，始终失败：DeviceA终端会显示PIN码及确认选项，但DeviceB无任何显示，最终连接超时。

HCI日志关键片段 #

< HCI Command: IO Capability Request Reply (0x01|0x002b) plen 9                 #21 [hci0] 10.668077
        Address: 58:63:9A:0B:75:28 (OUI 58-63-9A)
        IO capability: DisplayYesNo (0x01)
        OOB data: Authentication data not present (0x00)
        Authentication: Dedicated Bonding - MITM required (0x03)
> HCI Event: Command Complete (0x0e) plen 10                                    #22 [hci0] 10.668776
      IO Capability Request Reply (0x01|0x002b) ncmd 1
        Status: Success (0x00)
        Address: 58:63:9A:0B:75:28 (OUI 58-63-9A)
> HCI Event: IO Capability Response (0x32) plen 9                               #23 [hci0] 10.714623
        Address: 58:63:9A:0B:75:28 (OUI 58-63-9A)
        IO capability: DisplayYesNo (0x01)
        OOB data: Authentication data not present (0x00)
        Authentication: General Bonding - MITM not required (0x04)
> HCI Event: User Confirmation Request (0x33) plen 10                           #24 [hci0] 10.936580
        Address: 58:63:9A:0B:75:28 (OUI 58-63-9A)
        Passkey: 377842

日志显示双方IO能力、OOB数据配置一致，但认证类型不匹配：DeviceA使用Dedicated Bonding - MITM required，DeviceB使用General Bonding - MITM not required，这是配对失败的核心诱因。

设备信息 #

• DeviceB：待配对设备，支持Bluetooth 4.2和BLE 5.0，无法获取其日志
• DeviceA：基于Buildroot 2020的嵌入式硬件，搭载rs9116N芯片组
  • 蓝牙模块加载命令：

    rmmod rsi_sdio
    rmmod rsi_91x
    insmod bt/rsi_91x.ko dev_oper_mode=4
    insmod bt/rsi_sdio.ko
    

  • 曾尝试BT DUAL MODE 12模式，结果相同；dmesg显示加载正常：

    [  544.819149] rsi_91x: <==== Interface DOWN ====>
    [  544.828699] phone0: port 1(wlan0) entered disabled state
    [  544.863028] device wlan0 left promiscuous mode
    [  544.863067] phone0: port 1(wlan0) entered disabled state
    [  545.113488] rsi_91x: ***** Watch Dog Reset Successful *****
    [  546.324264] rsi_91x: rsi_reset_card: Set high speed mode
    [  546.336188] rsi_91x: ##### RSI SDIO device disconnected #####
    [  546.470461] rsi_91x: rsi_probe: ***** 9116 Module *****
    [  546.470807] rsi_91x: rsi_hal_device_init: oper_mode = 4, coex_mode = 2
    [  546.475523] rsi_91x: ================================================
    [  546.475553] rsi_91x: ================ RSI Version Info ==============
    [  546.475570] rsi_91x: ================================================
    [  546.475591] rsi_91x: FW Version  :  1610.2.3.0.0001
    [  546.475610] rsi_91x: Driver Version  : RS9116.NB0.NL.GNU.LNX.OSD.2.0.0.0024
    [  546.475627] rsi_91x: Operating mode  : 4 [BT EDR alone]
    [  546.475643] rsi_91x: Firmware file   : pmemdata_wlan_bt_classic
    [  546.475653] rsi_91x: ================================================
    [  546.571490] rsi_91x: ***** Firmware Loading successful *****
    

操作步骤 #

• 在单独终端运行蓝牙守护进程：bluetoothd -n
• 启动bluetoothctl
• 执行power on
• 执行scan on找到设备后关闭扫描
• 执行pair XX:XX

执行配对命令后，DeviceA终端显示PIN码及确认选项，但DeviceB无显示，最终连接超时。尝试过在不同时机执行trust XX:XX，无效果。

hciconfig -a输出 #

hci0:   Type: Primary  Bus: SDIO
    BD Address: 88:DA:1A:EB:84:E3  ACL MTU: 1021:3  SCO MTU: 64:3
    UP RUNNING PSCAN 
    RX bytes:15113 acl:0 sco:0 events:156 errors:0
    TX bytes:0 acl:0 sco:0 commands:75 errors:0
    Features: 0xbf 0xc6 0x0d 0x7e 0x9b 0x1f 0x59 0x87
    Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 
    Link policy: RSWITCH SNIFF 
    Link mode: SLAVE ACCEPT 
    Name: 'BlueZ 5.54'
    Class: 0x000000
    Service Classes: Unspecified
    Device Class: Miscellaneous, 
    HCI Version: 5.0 (0x9)  Revision: 0x100
    LMP Version: 5.0 (0x9)  Subversion: 0x100
    Manufacturer: not assigned (1791)

核心问题与解决建议 #

1. 强制统一认证类型：

   • 尝试通过bluetoothctl设置通用绑定模式：执行set bonding general，再发起配对
   • 编辑BlueZ配置文件/etc/bluetooth/main.conf，找到#Bonding = dedicated，改为Bonding = general，重启蓝牙服务后重试

2. 调整MITM要求：

   • 在bluetoothctl中执行set mitm off，关闭DeviceA的MITM强制要求，适配DeviceB的配置

3. 蓝牙版本兼容性调试：

   • DeviceA为Bluetooth 5.0，DeviceB支持4.2/5.0，理论兼容，但可尝试强制DeviceA使用经典蓝牙模式：在main.conf中设置ControllerMode = bredr，重启服务后测试

4. IO能力调整：

   • 在bluetoothctl中切换IO能力，比如执行set io-capability keyboardonly或set io-capability noinputnooutput，再尝试配对

5. 内核与固件检查：

   • 确认Buildroot编译时开启CONFIG_BT_BREDR、CONFIG_BT_SECURITY、CONFIG_BT_BONDING等核心蓝牙配置
   • 尝试升级rs9116N的驱动或固件到最新版本，修复绑定模式的兼容性问题

内容的提问来源于stack exchange，提问作者bkekelic