Android 拒绝连接 AVRCP 服务 (BlueZ-5.69)

Question

我的旧车没有原生蓝牙音频功能，因此要使用手机听音乐，我将蓝牙接收器连接到车上的 3.5 毫米辅助插孔。问题是控制手机上的播放，而无需在驾驶时操作手机（您知道这是违法的>:)）。

因此，我想到一个有趣的周末项目是将我的 Banana Pi 连接到汽车的 CAN 总线，以便监听方向盘上的媒体按钮（在从 aux 播放时不使用），同时还拥有 Banana Pi充当手机的 A/V 媒体控制器，通过蓝牙连接来控制手机媒体播放器。

所有这一切中最简单的部分是连接和嗅探 CAN 总线。蓝牙部分，没有那么多。 （还记得为什么我大约 20 年没有碰过任何蓝牙东西吗？）

我在 Arch Linux 下使用 BlueZ-5.69。我已禁用除 AVRCP 配置文件之外的所有功能。

[bluetooth]# show
Controller AA:AA:AA:AA:AA:AA (public)
  Name: "Car Controller"
  Alias: "Car Controller"
  Class: 0x0000050c (1292)
  Powered: yes
  PowerState: on
  Discoverable: no
  DiscoverableTimeout: 0x000000b4 (180)
  Pairable: yes
  UUID: PnP Information           (00001200-0000-1000-8000-00805f9b34fb)
  UUID: A/V Remote Control Target (0000110c-0000-1000-8000-00805f9b34fb)
  UUID: A/V Remote Control        (0000110e-0000-1000-8000-00805f9b34fb)
  Modalias: usb:v1D6Bp0246d0545
  Discovering: no
  Roles: central
  Roles: peripheral
  ExperimentalFeatures: BlueZ Experimental ISO... (6fbaf188-05e0-496a-9885-d6ddfdb4e03e)

据我了解，这应该允许手机连接，并且媒体播放器控件应该通过dbus.发现和配对似乎工作正常，但配对完成后，手机断开连接并拒绝再次连接（我实际上尝试使用 bt-network 设置 NAP 配置文件，现在手机实际上使用提供的网络保持连接） 。

这就是从角度来看手机配对时所发生的情况bluetoothctl。

[NEW] Device 3C:38:F4:93:55:61 Xperia 10 Ⅳ
Request confirmation
[agent] Confirm passkey 935792 (yes/no): yes
[CHG] Device 3C:38:F4:93:55:61 Bonded: yes
[CHG] Device 3C:38:F4:93:55:61 Modalias: usb:v0FCEp020Cd0010
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001105-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 0000110a-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001112-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001116-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 0000111f-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 0000112f-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001132-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001800-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: 00001801-0000-1000-8000-00805f9b34fb
[CHG] Device 3C:38:F4:93:55:61 UUIDs: a82efa21-ae5c-3dde-9bbc-f16da7b16c5a
[CHG] Device 3C:38:F4:93:55:61 ServicesResolved: yes
[CHG] Device 3C:38:F4:93:55:61 Paired: yes
[CHG] Device 3C:38:F4:93:55:61 ServicesResolved: no
[CHG] Device 3C:38:F4:93:55:61 Connected: no

还有bleutoothd日志

Sep 22 14:52:32 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] event 0x000b
Sep 22 14:52:32 alarm bluetoothd[628]: src/adapter.c:connected_callback() hci0 device 3C:38:F4:93:55:61 connected eir_len 20
Sep 22 14:52:32 alarm bluetoothd[628]: src/device.c:device_create() dst 3C:38:F4:93:55:61
Sep 22 14:52:32 alarm bluetoothd[628]: src/device.c:device_new() address 3C:38:F4:93:55:61
Sep 22 14:52:32 alarm bluetoothd[628]: src/device.c:device_new() Creating device /org/bluez/hci0/dev_3C_38_F4_93_55_61
Sep 22 14:52:32 alarm bluetoothd[628]: src/device.c:device_set_class() /org/bluez/hci0/dev_3C_38_F4_93_55_61 0x5A020C
Sep 22 14:52:32 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] event 0x000f
Sep 22 14:52:32 alarm bluetoothd[628]: src/adapter.c:user_confirm_request_callback() hci0 3C:38:F4:93:55:61 confirm_hint 0
Sep 22 14:52:32 alarm bluetoothd[628]: src/device.c:new_auth() Requesting agent authentication for 3C:38:F4:93:55:61
Sep 22 14:52:32 alarm bluetoothd[628]: src/agent.c:agent_ref() 0x1752050: ref=2
Sep 22 14:52:32 alarm bluetoothd[628]: src/agent.c:agent_request_confirmation() Calling Agent.RequestConfirmation: name=:1.62, path=/org/bluez/agent, passkey=935792
Sep 22 14:52:37 alarm bluetoothd[628]: src/agent.c:agent_ref() 0x1752050: ref=3
Sep 22 14:52:37 alarm bluetoothd[628]: src/adapter.c:btd_adapter_confirm_reply() hci0 addr 3C:38:F4:93:55:61 success 1
Sep 22 14:52:37 alarm bluetoothd[628]: src/agent.c:agent_unref() 0x1752050: ref=2
Sep 22 14:52:37 alarm bluetoothd[628]: src/agent.c:agent_unref() 0x1752050: ref=1
Sep 22 14:52:37 alarm bluetoothd[628]: src/shared/mgmt.c:send_request() [0x0000] command 0x001c
Sep 22 14:52:37 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] command 0x001c complete: 0x00
Sep 22 14:52:39 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] event 0x0009
Sep 22 14:52:39 alarm bluetoothd[628]: src/adapter.c:new_link_key_callback() hci0 new key for 3C:38:F4:93:55:61 type 8 pin_len 0 store_hint 1
Sep 22 14:52:39 alarm bluetoothd[628]: src/device.c:device_set_bonded() setting bonded for device to true
Sep 22 14:52:39 alarm bluetoothd[628]: src/device.c:btd_device_set_temporary() temporary 0
Sep 22 14:52:39 alarm bluetoothd[628]: src/device.c:device_bonding_complete() bonding (nil) status 0x00
Sep 22 14:52:39 alarm bluetoothd[628]: src/device.c:device_bonding_complete() setting timer for reverse service discovery
Sep 22 14:52:39 alarm bluetoothd[628]: src/adapter.c:resume_discovery()
Sep 22 14:52:39 alarm bluetoothd[628]: src/shared/mgmt.c:send_request() [0x0000] command 0x0033
Sep 22 14:52:39 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] event 0x002a
Sep 22 14:52:39 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] command 0x0033 complete: 0x00
Sep 22 14:52:39 alarm bluetoothd[628]: src/adapter.c:add_accept_list_complete() 3C:38:F4:93:55:61 added to kernel accept list
Sep 22 14:52:41 alarm bluetoothd[628]: profiles/audio/avrcp.c:avrcp_controller_probe() path /org/bluez/hci0/dev_3C_38_F4_93_55_61
Sep 22 14:52:41 alarm bluetoothd[628]: profiles/audio/control.c:control_init() Registered interface org.bluez.MediaControl1 on path /org/bluez/hci0/dev_3C_38_F4_93_55_61
Sep 22 14:52:41 alarm bluetoothd[628]: src/service.c:btd_service_ref() 0x17458d0: ref=2
Sep 22 14:52:41 alarm bluetoothd[628]: src/service.c:change_state() 0x17458d0: device 3C:38:F4:93:55:61 profile avrcp-controller state changed: unavailable -> disconnected (0)
Sep 22 14:52:41 alarm bluetoothd[628]: profiles/audio/avrcp.c:avrcp_target_probe() path /org/bluez/hci0/dev_3C_38_F4_93_55_61
Sep 22 14:52:41 alarm bluetoothd[628]: src/service.c:btd_service_ref() 0x17524c0: ref=2
Sep 22 14:52:41 alarm bluetoothd[628]: src/service.c:change_state() 0x17524c0: device 3C:38:F4:93:55:61 profile audio-avrcp-target state changed: unavailable -> disconnected (0)
Sep 22 14:52:41 alarm bluetoothd[628]: src/device.c:device_svc_resolved() /org/bluez/hci0/dev_3C_38_F4_93_55_61 err 0
Sep 22 14:52:47 alarm bluetoothd[628]: src/shared/mgmt.c:can_read_data() [0x0000] event 0x000c
Sep 22 14:52:47 alarm bluetoothd[628]: src/adapter.c:dev_disconnected() Device 3C:38:F4:93:55:61 disconnected, reason 3
Sep 22 14:52:47 alarm bluetoothd[628]: src/adapter.c:adapter_remove_connection()
Sep 22 14:52:47 alarm bluetoothd[628]: src/adapter.c:bonding_attempt_complete() hci0 bdaddr 3C:38:F4:93:55:61 type 0 status 0xe
Sep 22 14:52:47 alarm bluetoothd[628]: src/device.c:device_bonding_complete() bonding (nil) status 0x0e
Sep 22 14:52:47 alarm bluetoothd[628]: src/device.c:device_bonding_failed() status 14

阅读这一行Sep 22 14:52:41 alarm bluetoothd[628]: profiles/audio/control.c:control_init() Registered interface org.bluez.MediaControl1 on path /org/bluez/hci0/dev_3C_38_F4_93_55_61，它看起来很有希望，但仅一秒或更短时间后就会断开连接。

因此，在走到这一步之后，我在蓝牙标准的兔子洞里摸索了大约一周，实现了我自己的 AVRCP 配置文件和服务，直到我放弃。然后我挖出一部旧 iPhone 并将其与 Banana Pi 配对，然后按下手机上的连接按钮，这就是我得到的结果

[agent] Authorize service 0000110e-0000-1000-8000-00805f9b34fb (yes/no): yes
[NEW] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 [default]
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Repeat: off
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Shuffle: off
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Status: stopped
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: Title
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value:
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: TrackNumber
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value: 0x00000000 (0)
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: NumberOfTracks
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value: 0x00000000 (0)
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: Duration
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value: 0x00000000 (0)
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: Album
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value:
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: Artist
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value:
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Key: Genre
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Track Value:
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Position: 0x00000000 (0)
[CHG] Player /org/bluez/hci0/dev_58_E2_8F_62_31_7C/player0 Position: 0x00000000 (0)

有用！

所以我现在的问题是，为什么 iPhone 连接到媒体控制器服务没有任何问题，而任何 Android 手机（我有 3 部）在配对后甚至无法尝试连接？我在这里真的很茫然，所以任何见解将不胜感激。