peripheral_hids_keyboard only works with some hosts

[mlac]

Hi there,

I'm running the peripheral_hids_keyboard sample of the nRF Connect SDK 2.5.1 on my nRF52840-DK. After pushing button 4, advertising starts as expected, but I can only connect with some of my phones/tablets.

I can connect with:
- OnePlus 9 Pro phone running Android 13
- Huawei P20 Pro running Android 10

I can't connect with:
- MacBook Air running macOS Ventura 13.6.3 - After pressing the Connect button, a progress indicator shortly appears and then disappears.
- Huawei MediaPad M5 lite 10 tablet running Android 8.0.0 - Upon trying to pair, I get the "Pairing failed. Incorrect pairing key or the device you want to pair with is configured incorrectly" message.
- NPad-Pro tablet running Android 12 - "Pairing..." momentarily appears, then disappears.

The sample doesn't show up in the Bluetooth devices list:
- ThinkPad T520 running Windows 20 Pro 22H2

Can you reproduce such discrepancies across various hosts, and can you make them connect?

[Hung Bui]

Hi Mlac, 

Do you have any modification to the sample ? Do you use any filter accept list  ? 

Do you see any log on the NRF52 when you try to pair from those it can not connect ? 

I would suggest to try capture a sniffer trace so that we can inspect further. 

[mlac]

Hi Hung,

- As it turns out, the NPad-Pro tablet is a piece of crap that doesn't pair with any keyboard. :)
- The ThinkPad T520 doesn't list other BLE keyboards either. I think it has a Bluetooth classic module that doesn't support BLE.
- The Huawei MediaPad M5 lite 10 tablet actually works with the peripheral_hids_keyboard sample. I'm unsure why it didn't work the last time.

This leaves us with the MacBook Air running macOS Ventura 13.6.3. When trying to connect, I can see the following in the console:

Connected 10:B5:88:72:9A:E6 (public)
W: Ignoring data for unknown channel ID 0x003a
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 19)

Does the above ring a bell? (I've installed the sniffer, but filtering the device seems a bit tricky. I can try to capture a trace if still needed.)

Thanks for everything!

[Hung Bui]

Hi Mlac, 

Thanks for the trace. I can see that the nRF52840 rejected the pairing with "Unspecific reason". 

I'm checking internally to see why this happens. 
I assume you were testing with unmodified peripheral_hids_keyboard sample ? ( with CONFIG_NFC_OOB_PAIRING=n ?)
Could you send us the trace when it can connect and pair with other device not the MAC so we can compare ? 

Could you try testing with the peripheral_hids_mouse and check if you have the same problem (and give us the trace)

[Hung Bui]

Hi again, 
Please also add CONFIG_BT_SMP_LOG_LEVEL_DBG=y to the code and send us the log if it actually show any extra information on why it reject the pairing request. 

[mlac]

Hi Hung,

I haven't had CONFIG_NFC_OOB_PAIRING enabled, and I've enabled CONFIG_BT_SMP_LOG_LEVEL_DBG for the following tests as requested:

keyboard-mac.pcapng

Fullscreen keyboard-mac.txt Download

Advertisin successfully started
Advertising continued
D: conn 0x20001cb0 handle 0
D: chan 0x2000205c cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
W: Ignoring data for unknown channel ID 0x003a
D: Received SMP code 0x01 len 6
D: req: io_capability 0x04, oob_flag 0x00, auth_req 0x2D, max_key_size 0x10, init_key_dist 0x0B, resp_key_dist 0x0B
D: Unable to get keys for 10:B5:88:72:9A:E6 (public)
D: chan 0x2000205c cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 19)

keyboard-phone.pcapng

Fullscreen keyboard-phone.txt Download

Advertising successfully started
Advertising continued
D: conn 0x20001cb0 handle 0
D: chan 0x2000205c cid 0x0006
D: 
D: prnd 14912dac28b97ae452a0005dd6afb4e5
Connected AC:D6:18:1B:3D:B5 (public)
W: Unhandled ATT code 0x1d
D: Received SMP code 0x01 len 6
D: req: io_capability 0x04, oob_flag 0x00, auth_req 0x2D, max_key_size 0x10, init_key_dist 0x0F, resp_key_dist 0x0F
D: rsp: io_capability 0x01, oob_flag 0x00, auth_req 0x0D, max_key_size 0x10, init_key_dist 0x02, resp_key_dist 0x00
D: Received SMP code 0x0c len 64
D: 
D: 0x2000904c
D: Received SMP code 0x04 len 16
D: 
Passkey for AC:D6:18:1B:3D:B5 (public): 180785
Press Button 1 to confirm, Button 2 to reject.
D: Received SMP code 0x0d len 16
D: 
D: 
Numeric Match, conn 0x20001cb0
D: chan 0x2000205c conn 0x20001cb0 handle 0 encrypt 0x01 hci status 0x00
Security changed: AC:D6:18:1B:3D:B5 (public) level 4
D: Received SMP code 0x08 len 16
D: 
D: Received SMP code 0x09 len 7
D: identity AC:D6:18:1B:3D:B5 (public)
D: got status 0x0
Pairing completed: AC:D6:18:1B:3D:B5 (public), bonded: 1

mouse-mac.pcapng

Fullscreen mouse-mac.txt Download

D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
Direct advertising to EC:8C:9A:A8:4E:57 (public) started
D: chan 0x200020b4 cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 8)
Directed advertising failed to start
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Direct advertising to AC:D6:18:1B:3D:B5 (public) started
Direct advertising to AC:D6:18:1B:3D:B5 (public) timed out
Regular advertising started
D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
Direct advertising to EC:8C:9A:A8:4E:57 (public) started
D: chan 0x200020b4 cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 8)
Directed advertising failed to start
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Direct advertising to AC:D6:18:1B:3D:B5 (public) started
Direct advertising to AC:D6:18:1B:3D:B5 (public) timed out
Regular advertising started
D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
Direct advertising to EC:8C:9A:A8:4E:57 (public) started
D: chan 0x200020b4 cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 8)
Directed advertising failed to start
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Direct advertising to AC:D6:18:1B:3D:B5 (public) started
Direct advertising to AC:D6:18:1B:3D:B5 (public) timed out
Regular advertising started
D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
Direct advertising to EC:8C:9A:A8:4E:57 (public) started
D: chan 0x200020b4 cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 8)
Directed advertising failed to start
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Direct advertising to AC:D6:18:1B:3D:B5 (public) started
Direct advertising to AC:D6:18:1B:3D:B5 (public) timed out
Regular advertising started
D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected 10:B5:88:72:9A:E6 (public)
Direct advertising to EC:8C:9A:A8:4E:57 (public) started
D: chan 0x200020b4 cid 0x0006
Disconnected from 10:B5:88:72:9A:E6 (public) (reason 8)
Directed advertising failed to start
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Direct advertising to AC:D6:18:1B:3D:B5 (public) started
Direct advertising to AC:D6:18:1B:3D:B5 (public) timed out
Regular advertising started

mouse-phone.pcapng

Fullscreen mouse-phone.txt Download

D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
Connected AC:D6:18:1B:3D:B5 (public)
Direct advertising to E8C:9A:A8:4lic) started
Direct advertising to EC:8C:9A:A8:4E:57 (public) timed out
Regular advertising started
D: Received SMP code 0x01 len 6
D: req: io_capability 0x04, oob_flag 0x00, auth_req 0x2D, max_key_size 0x10, init_key_dist 0x0F, resp_key_dist 0x0F
D: prnd c9ee4a30a30d95e5df0128728d51e951
D: rsp: io_capability 0x01, oob_flag 0x00, auth_req 0x0D, max_key_size 0x10, init_key_dist 0x02, resp_key_dist 0x02
D: Received SMP code 0x0c len 64
D: 
D: 0x20008b05
D: Received SMP code 0x04 len 16
D: 
Passkey for AC:D6:18:1B:3D:B5 (public): 713638
Press Button  to confirm, Button 2ct.
Numeric Match, conn 0x20001d08
D: Received SMP code 0x0d len 16
D: 
D: 
D: chan 0x200020b4 conn 0x20001d08 handle 0 encrypt 0x01 hci status 0x00
Security changed: AC:D6:18:1B:3D:B5 (public) level 4
D: Received SMP code 0x08 len 16
D: 
D: Received SMP code 0x09 len 7
D: identity AC:D6:18:1B:3D:B5 (public)
D: got status 0x0
Pairing completed: AC:D6:18:1B:3D:B5 (public), bonded: 1
button_changed(): left
button_changed(): left

The phone connection attempts were successful, and the Mac connection attempts were unsuccessful.

[Hung Bui]

Hi Mlac, 

Regarding the trace between mouse and MAC, it doesn't seem they do pairing. Could you please test again and make sure the sniffer follows the mouse ? 
The log say "Unable to get keys for", it either returned by bt_keys_get_addr()  or bt_keys_get_type(). In both case it's related to that an old key can not be retracted or it can not create a new slot for the key. 
Have you made sure you erased the whole flash before testing ? I am under the impression that it reached the maximum number of device can be paired. 

Another option is to enable CONFIG_BT_KEYS_OVERWRITE_OLDEST so that it will overwrite the old key. 

If that doesn't help, could you add a breakpoint in the code where "Unable to get keys" is printed out in smp.c (there are 10 locations). We need to know which exact function causing the issue. 

[mlac]

Hi Hung,

I remembered that in a similarly strange but different situation when I upgraded my application to MCUboot, and it kept crashing shortly after boot, I used the `nrfjprog --recover` command successfully, and I tried it again for this issue, and it solved the problem for the keyboard sample.

How did `nrfjprog --recover` fix the issue? I'm starting to get dependent on this command without understanding what's happening in the background.

As for the mouse, now it pairs, but when I press the buttons, the mouse pointer doesn't move on the Mac, so I'm attaching the updated log and capture:

mouse-mac-2.pcapng

Fullscreen mouse-mac-2.txt Download

D: conn 0x20001d08 handle 0
D: chan 0x200020b4 cid 0x0006
I: BAS Notifications enabled
Connected 10:B5:88:72:9A:E6 (public)
Regular advertising started
W: Ignoring data for unknown channel ID 0x003a
button_changed(): right
button_changed(): left
button_changed(): up
button_changed(): down
button_changed(): right
button_changed(): right
button_changed(): right
button_changed(): left
button_changed(): left
button_changed(): left
button_changed(): left
button_changed(): up
button_changed(): up
button_changed(): up
button_changed(): up
button_changed(): up
button_changed(): down
button_changed(): down
button_changed(): down
button_changed(): down

[Hung Bui]

Hi mlac, 

When you do "nrfjprog --recover" the whole flash memory of the chip will be erased. If you simply erase and flash the new code without a full erase, the settings partition will retain, meaning all the bond in your test will still be in the flash. It could be the reason why you can't pair the MAC device because it exceed the maximum of pair information in the setting partition. 

From what I can see in the sniffer trace, the mouse did send the notification to the MAC. So there must be an issue interpreting the data on MAC that doesn't result in the mouse movement. 

One thing I noticed is that there were no pairing/bonding with the mouse. Could you check why ? It could be reason the MAC doesn't show mouse movement. 
 I assume the mouse works fine on other machine, correct ? 

Could you try using the nRF Desktop application ? It can also emulate a desktop mouse on a DK. 
https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/nrf_desktop/README.html#

[mlac]

Thanks for explaining what `nrfjprog --recover` does, Hung. It makes sense.

The nrf_desktop sample did work. I can connect it to my Mac, and the mouse pointer moves when pressing the buttons.

The peripheral_hids_mouse sample still doesn't work, even if I run `nrfjprog --recover` before flashing it, and my Mac doesn't remember any pairing information from before because when it does, it always offers to forget it for the device.

Would you be able to test peripheral_hids_mouse on a Mac? I use a MacBook Air M1, 2020 running macOS Ventura 13.6.3, but any new Mac with an M chip should work.

[Hung Bui]

Hi Mlac, 
I'm not so familiar with MAC device, but I did a test on a Macbook Air here and saw the same issue. 
Doesn't seem pairing is occurring. I will need to check internally here to see why. 
My suggestion in the mean time is to take a look at the nRF Desktop and check why it works with nRF Desktop but not the BLE mouse sample.

[mlac]

Thanks for confirming this bug, Hung. I will work on other parts of my project until this gets fixed.

I keep this conversation unresolved until the issue gets fixed.

[Hung Bui]

Hi mlac, 
Could you try testing the peripheral_hids_mouse again , this time with 

CONFIG_BT_HIDS_DEFAULT_PERM_RW_ENCRYPT=y 

It seems to work for me.