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author | Mat Martineau <mathewm@codeaurora.org> | 2010-08-05 15:54:27 -0700 |
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committer | Marcel Holtmann <marcel@holtmann.org> | 2010-08-10 07:59:11 -0400 |
commit | db12d647ccc971ed120199dc7ea5be2b5887d328 (patch) | |
tree | 6720ef2cbcd408fcca4c94b855970ca1e9908f3e /net | |
parent | cff70fae111efba80c27023772ce5265797fb514 (diff) | |
download | op-kernel-dev-db12d647ccc971ed120199dc7ea5be2b5887d328.zip op-kernel-dev-db12d647ccc971ed120199dc7ea5be2b5887d328.tar.gz |
Bluetooth: Use 3-DH5 payload size for default ERTM max PDU size
The previous value of 672 for L2CAP_DEFAULT_MAX_PDU_SIZE is based on
the default L2CAP MTU. That default MTU is calculated from the size
of two DH5 packets, minus ACL and L2CAP b-frame header overhead.
ERTM is used with newer basebands that typically support larger 3-DH5
packets, and i-frames and s-frames have more header overhead. With
clean RF conditions, basebands will typically attempt to use 1021-byte
3-DH5 packets for maximum throughput. Adjusting for 2 bytes of ACL
headers plus 10 bytes of worst-case L2CAP headers yields 1009 bytes
of payload.
This PDU size imposes less overhead for header bytes and gives the
baseband the option to choose 3-DH5 packets, but is small enough for
ERTM traffic to interleave well with other L2CAP or SCO data.
672-byte payloads do not allow the most efficient over-the-air
packet choice, and cannot achieve maximum throughput over BR/EDR.
Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net')
0 files changed, 0 insertions, 0 deletions