Android disconnect issues

RE: Android disconnect issues

Hung Bui — Fri, 22 Dec 2017 10:11:43 GMT

Could you try to use our sniffer ? What you provided is Android log. It doesn't provide all the information needed. I saw some connection established but then saw "Sent Disconnect" meaning it's disconnected by the phone.

In last softdevice, it's fixed by allowing the parallel LL link command for all LL commands (except 2 same LL commands) by default. So the compatible mode 2 is not needed. Note that compatible mode 2 only cover part of the LL commands, so there could be a chance that your central issue wasn't covered by Compat mode 2.

sd_ble_opt_get(BLE_GAP_OPT_COMPAT_MODE_2) always return code 7 , it's a bug and since this mode is deprecated in newer softdevice, we won't fix it.

RE: Android disconnect issues

KV — Thu, 21 Dec 2017 20:51:12 GMT

Thanks for the suggestion. This still did not fix the issue. I added the following lines of code which is executed once on power up (outside while(1) loop).

ble_stack_init();
peer_manager_init();
gap_params_init();
gatt_init();
advertising_data_set();

// initiliaze BLE parameters
gatt_mtu_set(ble_params.att_mtu);
data_len_ext_set(ble_params.data_len_ext_enabled);
conn_evt_len_ext_set(ble_params.conn_evt_len_ext_enabled);
preferred_phy_set(&ble_params.phys);

//st compatibility mode to 2 for samsung Tab-A disconnect issues
ret_code_t err_code;
ble_opt_t  opt;       
memset(&opt, 0x00, sizeof(opt));
opt.gap_opt.compat_mode_2.enable = 1;
err_code = sd_ble_opt_set(BLE_GAP_OPT_COMPAT_MODE_2 , &opt);
APP_ERROR_CHECK(err_code);

When I use the sd_ble_opt_get to read back the option (just to confirm) this soft device API returns error code 7 (invalid param). not sure what is wrong with this code below:

 memset(&opt, 0x00, sizeof(opt));
err_code = sd_ble_opt_get(BLE_GAP_OPT_COMPAT_MODE_2 , &opt);
APP_ERROR_CHECK(err_code);
NRF_LOG_INFO("compatiblity get:%d", opt.gap_opt.compat_mode_2.enable);

Also, I noticed that in the latest soft device v6 release notes that this issue has been fixed (DRGN-8623). Is that correct?

RE: Android disconnect issues

Madhu — Thu, 21 Dec 2017 20:47:34 GMT

@Hung Bui Please find the attached sniffer trace from Android device Samsung Tab A SM-T580 with Bluetooth version 4.2. btsnoop_hci.log

RE: Android disconnect issues

Hung Bui — Thu, 21 Dec 2017 16:26:16 GMT

Hi KV, On S140 v5.0, the feature is not enabled by default. You can try enable compatibility mode 2 BLE_GAP_OPT_COMPAT_MODE_2 using the sd_ble_opt_set() function. Your case may be similar to this case.

RE: Android disconnect issues

KV — Thu, 21 Dec 2017 15:21:24 GMT

SDK 14.2.0 and Soft device S140 version 5.0.0.-2_alpha. The soft device v6 is not compatible with the latest SDK.

The disconnected reason is BLE_HCI_DIFFERENT_TRANSACTION_COLLISION.

I am trying to set up the latest sniffer (beta release v2.0) with Wireshark and it is functioning intermittently. Sometimes the COM port does not get detected.

RE: Android disconnect issues

Hung Bui — Thu, 21 Dec 2017 13:25:17 GMT

@KV: Please provide a sniffer trace.

Please state which SDK and which Softdevice you used. Also please confirm you have disconnected reason = 0x2A = BLE_HCI_DIFFERENT_TRANSACTION_COLLISION, this disconnect reason usually happens when the peer (the phone) violate the spec and send 2 LL link layer request without waiting for response. In S132 we allowed the behaviour. From release note:

The SoftDevice slave role now accepts overlapping peer-initiated Link Layer control procedures (DRGN-8623). The following LL control procedures can be executed in parallel with any other control procedure, except for themselves: LEPing, Feature Exchange, Data Length Update, and Version Exchange. This is done for compatibility reasons.

RE: Android disconnect issues

endnode — Thu, 21 Dec 2017 07:33:52 GMT

If you have problem with some buggy blackbox (here made by Samsung) failing in BLE connection then you will need Network analyzer/BLE sniffer to understand what happens there.