Hi , Kernel has set some restrictions in simultaneous L2cap data transfer on BLE and ACL links on a common device . My test scenario is as follows Device A has both LE and ACL link with device B and C respectively . when i start sending l2cap data on ACL link (A to B), it work fine . But when i starts sending BLE data along with ACL data (A to C ) , it fails with error "send failed : interrupt system call" . when i count the LE packets that had reached upto hci layer , it shows some 367 packets. Later i noticed that LE data is getting queued at hci layer and it is not scheduled properly . following piece of code tells us the order of scheduling.. (hci_core.c) static void hci_tx_task(unsigned long arg) { struct hci_dev *hdev = (struct hci_dev *) arg; struct sk_buff *skb; read_lock(&hci_task_lock); BT_DBG("%s acl %d sco %d le %d", hdev->name, hdev->acl_cnt, hdev->sco_cnt, hdev->le_cnt); /* Schedule queues and send stuff to HCI driver */ hci_sched_acl(hdev); hci_sched_sco(hdev); hci_sched_esco(hdev); hci_sched_le(hdev); ...... Here both acl and le scheduling are using same count as reference (hdev->acl_cnt) and they have never make use of hdev->le_cnt. please kindly go through this issue. -- Thanks & Regards AJAY KV GlobalEdge software Ltd 8892753703