This patch tolerates connection parameters that were valid before ESR08_v1.0.0 which was also incoporated into the 4.2 core specification. In particular, this addresses compatibility issues with the Lenovo Yoga Mouse that sees its connection parameters rejected by the max_latency computation in hci_conn_check_params, but was perfectly valid at the time this mouse was qualified. Before the patch, the mouse was extremely laggy, after the patch, the mouse worked as expected. Signed-off-by: Alain Michaud <alainm@xxxxxxxxxxxx> Reviewed-by: Miao-chen Chou <mcchou@xxxxxxxxxxxx> Tested-by: Harry Cutts <hcutts@xxxxxxxxxxxx> --- include/net/bluetooth/hci_core.h | 30 ++++++++++++++++++++++++++++++ net/bluetooth/l2cap_core.c | 12 ++++++++++++ 2 files changed, 42 insertions(+) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index ebdd4afe30d2..67b75077c82e 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -1646,6 +1646,36 @@ static inline struct smp_irk *hci_get_irk(struct hci_dev *hdev, return hci_find_irk_by_rpa(hdev, bdaddr); } +/* Erratum 5412 which has been fixed in 4.2 changed the validation of + * connection parameters. For backwards compatibility reasons, the old + * calculation must be tolerated. + * For further details : + * https://www.bluetooth.org/errata/errata_view.cfm?errata_id=5419 + */ +static inline int hci_check_conn_params_legacy(u16 min, u16 max, u16 latency, + u16 to_multiplier) +{ + u16 max_latency; + + if (min > max || min < 6 || max > 3200) + return -EINVAL; + + if (to_multiplier < 10 || to_multiplier > 3200) + return -EINVAL; + + if (max >= to_multiplier * 8) + return -EINVAL; + + max_latency = (to_multiplier * 8 / max) - 1; + if (latency > 499 || latency > max_latency) + return -EINVAL; + + return 0; +} + +/* Connection Parameter Validation Helper. + * See Vol 6, Part B, section 4.5.1. + */ static inline int hci_check_conn_params(u16 min, u16 max, u16 latency, u16 to_multiplier) { diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 72c2f5226d67..726e78bd85ff 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5553,6 +5553,18 @@ static inline int l2cap_conn_param_update_req(struct l2cap_conn *conn, memset(&rsp, 0, sizeof(rsp)); err = hci_check_conn_params(min, max, latency, to_multiplier); + if (err) { + BT_WARN("Invalid conn params min 0x%4.4x max 0x%4.4x latency: 0x%4.4x TO: 0x%4.4x", + min, max, latency, to_multiplier); + + err = hci_check_conn_params_legacy(min, max, latency, + to_multiplier); + if (!err) { + /* latency is invalid, cap it to the max allowed */ + latency = min(499, (to_multiplier * 4 / max) - 1); + } + } + if (err) rsp.result = cpu_to_le16(L2CAP_CONN_PARAM_REJECTED); else -- 2.30.0.478.g8a0d178c01-goog
