Re: [PATCH v1] Bluetooth: hci_event: Add HCI_Write_Link_Supervision_Timeout command/event structures

Hi,

On Thu, Jul 23, 2026 at 6:05 AM <[email protected]> wrote:
>
> From: Chen Zhang <[email protected]>
>
> Define HCI_Write_Link_Supervision_Timeout command, event structure, and
> corresponding event handler function.
>
> Signed-off-by: Chen Zhang <[email protected]>
> ---
>  include/net/bluetooth/hci.h      | 10 ++++++++
>  include/net/bluetooth/hci_core.h |  1 +
>  net/bluetooth/hci_event.c        | 40 ++++++++++++++++++++++++++++++++
>  3 files changed, 51 insertions(+)
>
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 50f0eef71fb1..18a5a17eb218 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -1239,6 +1239,16 @@ struct hci_cp_host_buffer_size {
>         __le16   sco_max_pkt;
>  } __packed;
>
> +#define HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT  0x0c37
> +struct hci_cp_write_link_supervision_timeout {
> +       __le16   handle;
> +       __le16   timeout;
> +} __packed;
> +struct hci_rp_write_link_supervision_timeout {
> +       __u8     status;
> +       __le16   handle;
> +} __packed;
> +
>  #define HCI_OP_READ_NUM_SUPPORTED_IAC  0x0c38
>  struct hci_rp_read_num_supported_iac {
>         __u8    status;
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index e7133ff87fbf..866903a9b5c8 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -702,6 +702,7 @@ struct hci_conn {
>         __u8            le_features[248];
>         __u16           pkt_type;
>         __u16           link_policy;
> +       __u16           link_supervision_timeout;
>         __u8            key_type;
>         __u8            auth_type;
>         __u8            sec_level;
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 741d658e9630..3b1f4cf922c3 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -606,6 +606,44 @@ static u8 hci_cc_write_voice_setting(struct hci_dev *hdev, void *data,
>         return rp->status;
>  }
>
> +static u8 hci_cc_write_link_supervision_timeout(struct hci_dev *hdev, void *data,
> +                                               struct sk_buff *skb)
> +{
> +       struct hci_ev_status *rp = data;
> +       struct hci_cp_write_link_supervision_timeout *sent;
> +       struct hci_conn *conn;
> +       u16 handle;
> +       u8 status = rp->status;
> +
> +       bt_dev_dbg(hdev, "status 0x%2.2x", status);
> +
> +       sent = hci_sent_cmd_data(hdev, HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT);
> +       if (!sent)
> +               return status;
> +
> +       handle = le16_to_cpu(sent->handle);
> +
> +       hci_dev_lock(hdev);
> +
> +       conn = hci_conn_hash_lookup_handle(hdev, handle);
> +       if (!conn) {
> +               status = 0xFF;
> +               goto done;
> +       }
> +
> +       if (!status) {
> +               conn->link_supervision_timeout = __le16_to_cpu(sent->timeout);
> +               bt_dev_dbg(hdev, "handle 0x%4.4x timeout set to 0x%4.4x (%u ms)",
> +                          handle, conn->link_supervision_timeout,
> +                          conn->link_supervision_timeout * 5 / 8);
> +       }
> +
> +done:
> +       hci_dev_unlock(hdev);
> +
> +       return status;
> +}
> +
>  static u8 hci_cc_read_num_supported_iac(struct hci_dev *hdev, void *data,
>                                         struct sk_buff *skb)
>  {
> @@ -4097,6 +4135,8 @@ static const struct hci_cc {
>         HCI_CC_STATUS(HCI_OP_WRITE_CLASS_OF_DEV, hci_cc_write_class_of_dev),
>         HCI_CC(HCI_OP_READ_VOICE_SETTING, hci_cc_read_voice_setting,
>                sizeof(struct hci_rp_read_voice_setting)),
> +       HCI_CC(HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT, hci_cc_write_link_supervision_timeout,
> +              sizeof(struct hci_rp_write_link_supervision_timeout)),

Ok, but I don't see use sending the
HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT command, so what is this for,
handling some custom entity that does perform this sort of operation
behind bluetoothd back is not an acceptable excuse.

>         HCI_CC_STATUS(HCI_OP_WRITE_VOICE_SETTING, hci_cc_write_voice_setting),
>         HCI_CC(HCI_OP_READ_NUM_SUPPORTED_IAC, hci_cc_read_num_supported_iac,
>                sizeof(struct hci_rp_read_num_supported_iac)),
> --
> 2.25.1
>
>


-- 
Luiz Augusto von Dentz