sd_softdevice_disable() causes application to crash/hang if device is paired

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

Susheel Nuguru — Thu, 03 Sep 2015 10:34:15 GMT

Thanks for updating this thread.

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

ned_zeppelin — Thu, 03 Sep 2015 10:26:48 GMT

Hi, I was finally able to do some proper debugging. I was incorrect in assuming that sd_softdevice_disable() caused the program to halt. The reason my uart printout directly after sd_softdevice_disable() did not appear is that I call sd_mutex_acquire() before every printout, and abort if NRF_SUCCESS is not returned. In this case the softdevice had been disabled so the printout was aborted.

However, dm_application_context_set(), called from dfu_app_handler.c, returns (NRF_ERROR_INVALID_STATE | DEVICE_MANAGER_ERR_BASE) (due to VERIFY_DEVICE_BOND(p_handle->connection_id) failing), causing the app_error_handler() to be called.

The first line of my app_error_handler is APP_ERROR_CHECK(sd_nvic_critical_region_enter(0)), which is probably what caused program execution to "hang" (as the softdevice had been disabled).

I was able to recreate it using the ble_app_hrs example with dfu from sdk 8.1.0 by adjusting the security settings etc., but the issue was as explained above not sd_softdevice_disable().

The bug was in my code and not the SDK or Softdevice. The DEVICE_MANAGER_APP_CONTEXT_SIZE define should be set to 0, if pairing (but not bonding) is performed.

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

Susheel Nuguru — Tue, 01 Sep 2015 07:49:51 GMT

I cannot reproduce this within the examples we have, can i try your project?

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

ned_zeppelin — Mon, 31 Aug 2015 16:08:37 GMT

Yes, the following function is called to do this:

static void reset_prepare(void)
{
    uint32_t err_code;

    if (m_conn_handle != BLE_CONN_HANDLE_INVALID)
    {
        // Disconnect from peer.
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
        APP_ERROR_CHECK(err_code);
    }
    else
    {
        // If not connected, the device will be advertising. Hence stop the advertising.
        advertising_stop();
    }

    err_code = ble_conn_params_stop();
    APP_ERROR_CHECK(err_code);

    nrf_delay_ms(500);
}
/** @snippet [DFU BLE Reset prepare] */
#endif // BLE_DFU_APP_SUPPORT

In context, this is what happens before sd_softdevice_disable() is called (when DFU is triggered):

uint32_t err_code;
uint16_t sys_serv_attr_len = sizeof(m_peer_data.sys_serv_attr);

err_code = sd_ble_gatts_sys_attr_get(conn_handle,
                                     m_peer_data.sys_serv_attr,
                                     &sys_serv_attr_len,
                                     BLE_GATTS_SYS_ATTR_FLAG_SYS_SRVCS);
if (err_code != NRF_SUCCESS)
{
    // Any error at this stage means the system service attributes could not be fetched.
    // This means the service changed indication cannot be sent in DFU mode, but connection
    // is still possible to establish.
}

m_reset_prepare();

err_code = sd_power_gpregret_set(BOOTLOADER_DFU_START);
APP_ERROR_CHECK(err_code);

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

Susheel Nuguru — Mon, 31 Aug 2015 10:10:54 GMT

have you made sure to stop all BLE activity before calling this? like stopping advertising and scanning or disconnecting any active connection(s)?

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

ned_zeppelin — Fri, 28 Aug 2015 07:42:10 GMT

I am not sure, as I am using UART printouts for debugging at this point. But the program halts after sd_softdevice_disable() is called, meaning program execution never returns from the point where the function is called. There is no reset. I have adjusted my watchdog timeout to 10 seconds for testing, and this eventually resets the system.

Although I cannot be sure, I suspect the situation is reproducible by using an example from sdk 8.1.0 which supports entering DFU from the application (using my security parameters). I say this because the issue disappears when setting SEC_PARAM_BOND to '1'. It also disappears if pairing is not performed at all.

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

Susheel Nuguru — Fri, 28 Aug 2015 06:49:24 GMT

what does it mean by system crash? Is it hardfaulting or does your application does a system reset in some error handler?

RE: sd_softdevice_disable() causes application to crash/hang if device is paired

ned_zeppelin — Thu, 27 Aug 2015 18:42:51 GMT

If I set SEC_PARAM_BOND to '1', it doesn't crash. Are my (initial) security parameters invalid, or is this a bug?