BLE_L2CAP_CH_STATUS_CODE_NO_RESOURCES event is coming when when remote device sends l2cap connection request

[dhilshad]

I am using Nordic Serialisation library, with a nrf52480 chip as connectivity chip and a m4 arm core custom board as Application chip. I am able to establish gap connection from Remote device. But when remote device send request to connect to l2cap channel (with PSM value 129, just for experimentation purpose, I set this value), I am getting BLE Event BLE_L2CAP_CH_STATUS_CODE_NO_RESOURCES from connecticity chip. There is no L2cap request event or anything. .I am directly getting this event. I mean, 

BLE_L2CAP_EVT_CH_SETUP_REFUSED event with status as BLE_L2CAP_CH_STATUS_CODE_NO_RESOURCES.

I have set the l2cap connection configuration as below:

	ble_cfg_t ble_cfg;
	ble_cfg.conn_cfg.conn_cfg_tag = APP_BLE_CONN_CFG_TAG; /* = 1 */
	ble_cfg.conn_cfg.params.l2cap_conn_cfg.ch_count = 1;	
	ble_cfg.conn_cfg.params.l2cap_conn_cfg.rx_mps = 67;
	ble_cfg.conn_cfg.params.l2cap_conn_cfg.tx_mps = 67;
	ble_cfg.conn_cfg.params.l2cap_conn_cfg.rx_queue_size = 4;
	ble_cfg.conn_cfg.params.l2cap_conn_cfg.tx_queue_size = 4;
	err_code = sd_ble_cfg_set(BLE_CONN_CFG_L2CAP, &ble_cfg, NULL);

[Vidar Berg]

Based on Kenneth's reply it sounds like the Softdevice has not been properly configured to support the additional l2cap channel. Is it possible to attach a debugger to the connectivity board or enable logging to check if the BLE_CONN_CFG_L2CAP config parameters passed to sd_ble_cfg_set() match the ones you sent from the host cpu?

And just to be sure, you started connectable advertising with the same APP_BLE_CONN_CFG_TAG=1 tag?

[dhilshad]

Hi,

I have found the root cause of this issue. This is a issue in Nordic serialisation library.
In ble_cfg_set_req_enc fucntion, conn_cfg_tag is only encoded for API till GATT APIs. For L2CAP APIs this is not encoded. And also, in connectivity chip side also, this is not decoded for L2CAP Apis

[Vidar Berg]

Sorry, I was not aware of this limitation. I assumed all the APIs had been serialized. Thanks for reporting back.