Bluetooth: Host: ACL/ISO buffers and bt_conn_tx objects mismatch #2868
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… ACL/ISO bufs After zephyrproject-rtos/zephyr#72090, each packet to be sent (wether ACL or ISO data) has a corresponding `bt_conn_tx` object, regardless of whether a callback is used. This means that number of packets Host can send to Controller is limited by the smaller of two values: ACL/ISO packets Controller can receive, and the number of `bt_conn_tx` objects allocated by Host. A mismatch between these numbers may lead to inefficient resource usage on either Host or Controller side. If Host allocates fewer `bt_conn_tx` objects than the number of buffers available on Controller for a given data type, some Controller buffers may go unused. Conversely, if Host allocates more `bt_conn_tx` objects than Controller can consume, the excess objects remain unused. This commit adds a check and issues a warning if the number of `bt_conn_tx` objects is not aligned with the number of ACL/ISO buffers reported by Controller via the LE Read Buffer Size v1 or v2 command. Signed-off-by: Pavel Vasilyev <[email protected]> (cherry picked from commit ddeeecd)
After zephyrproject-rtos/zephyr#72090, `conn_tx_alloc` no longer blocks, and each buffer always has a corresponding `bt_conn_tx` object. This eliminates the need to configure the number of `bt_conn_tx` objects via `CONFIG_BT_CONN_TX_MAX`, since every buffer now carries its own context even when no callback is used. This commit deprecates `CONFIG_BT_CONN_TX_MAX` as it is no longer necessary. Instead, `CONFIG_BT_BUF_ACL_TX_COUNT` is used to allocate `bt_conn_tx` objects for outgoing ACL data. ZLL already uses `CONFIG_BT_BUF_ACL_TX_COUNT` to configure the number of outgoing ACL packets. With this change, modifying the packet count will automatically adjust the number of corresponding contexts, preventing both context starvatoin and underutilization. This approach also aligns with ISO, where the number of `bt_conn_tx` objects for outgoing ISOdata matches `CONFIG_BT_ISO_TX_BUF_COUNT`. Signed-off-by: Pavel Vasilyev <[email protected]> (cherry picked from commit 14b4e30)
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Will be downstreamed with upmerge |
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Upstream PR #: 89258
Task: NCSDK-31338