Since net_buf_get() for the avail_acl_tx FIFO is called in
interrupt context (ISR) it cannot wait, and it will fail
immediately returning NULL if it fails to acquire a buffer.
During LE Secure Connections pairing, when there is a fair
amount of packets coming from the host, the FIFO was running
out of buffers causing the packet to be dropped instead of
forwarding it to the controller.
The number allocated now matches the amount of TX buffers
in the controller, so that normal HCI flow control (from
the Host to the Controller) will kick-in preventing any
buffers from being dropped.
Change-Id: Ifad4fbac84ae938eb0e68b73a80a02ba79b6ff6e
Signed-off-by: Carles Cufi <carles.cufi@nordicsemi.no>
17f7a3cf74