Help¶

Maximum data size for each HCI RX buffer. This size includes everything starting with the ACL or HCI event headers. Note that buffer sizes are always rounded up to the nearest multiple of 4, so if this Kconfig value is something else then there will be some wasted space. The minimum of 73 has been taken for LE SC which has an L2CAP MTU of 65 bytes. On top of this there’s the L2CAP header (4 bytes) and the ACL header (also 4 bytes) which yields 73 bytes.

Direct dependencies¶

BT_HCI && BT

(Includes any dependencies from ifs and menus.)

Defaults¶

264 if BT_BREDR
258 if BT_EXT_ADV
77 if BT_MESH_PROXY
76

Kconfig definition¶

At subsys/bluetooth/host/Kconfig:34

Included via Kconfig:8 → Kconfig.zephyr:34 → subsys/Kconfig:9 → subsys/bluetooth/Kconfig:239

Menu path: (Top) → Sub Systems and OS Services → Bluetooth

config BT_RX_BUF_LEN
    int "Maximum supported HCI RX buffer length"
    range 73 2000
    default 264 if BT_BREDR
    default 258 if BT_EXT_ADV
    default 77 if BT_MESH_PROXY
    default 76
    depends on BT_HCI && BT
    help
      Maximum data size for each HCI RX buffer. This size includes
      everything starting with the ACL or HCI event headers. Note that
      buffer sizes are always rounded up to the nearest multiple of 4,
      so if this Kconfig value is something else then there will be some
      wasted space. The minimum of 73 has been taken for LE SC which has
      an L2CAP MTU of 65 bytes. On top of this there's the L2CAP header
      (4 bytes) and the ACL header (also 4 bytes) which yields 73 bytes.

(The ‘depends on’ condition includes propagated dependencies from ifs and menus.)