Re: [PATCH] Bluetooth: mgmt: report extended advertising SID to userspace

[Luiz Augusto von Dentz]

Hi Yang,

On Wed, Jan 7, 2026 at 3:48 AM Yang Li via B4 Relay
<devnull+yang.li.amlogic.com@xxxxxxxxxx> wrote:
>
> From: Yang Li <yang.li@xxxxxxxxxxx>
>
> Add a new mgmt event to report the SID of extended advertising
> to userspace. This allows userspace to obtain the SID before
> initiating PA sync, without waiting for the next extended
> advertising report to update the SID.
>
> By providing the SID earlier, the PA sync flow can be simplified
> and the overall latency reduced.
>
> Link: https://github.com/bluez/bluez/issues/1758

This is a new API so it can't possible fix the userspace issue above,
there is clearly a bug when sid is set to 0xff we shall not proceed
until it is resolved.

> Signed-off-by: Yang Li <yang.li@xxxxxxxxxxx>
> ---
>  include/net/bluetooth/hci_core.h |  2 ++
>  include/net/bluetooth/mgmt.h     |  7 +++++++
>  net/bluetooth/hci_event.c        |  3 +++
>  net/bluetooth/mgmt.c             | 13 +++++++++++++
>  4 files changed, 25 insertions(+)
>
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index a7bffb908c1e..81ef3e94e3af 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -2469,6 +2469,8 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>                        u8 addr_type, u8 *dev_class, s8 rssi, u32 flags,
>                        u8 *eir, u16 eir_len, u8 *scan_rsp, u8 scan_rsp_len,
>                        u64 instant);
> +void mgmt_ext_adv_sid_changed(struct hci_dev *hdev, bdaddr_t *bdaddr,
> +                                    u8 addr_type, u8 sid);
>  void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>                       u8 addr_type, s8 rssi, u8 *name, u8 name_len);
>  void mgmt_discovering(struct hci_dev *hdev, u8 discovering);
> diff --git a/include/net/bluetooth/mgmt.h b/include/net/bluetooth/mgmt.h
> index 8234915854b6..7ee38ebaccd8 100644
> --- a/include/net/bluetooth/mgmt.h
> +++ b/include/net/bluetooth/mgmt.h
> @@ -1195,3 +1195,10 @@ struct mgmt_ev_mesh_device_found {
>  struct mgmt_ev_mesh_pkt_cmplt {
>         __u8    handle;
>  } __packed;
> +
> +#define MGMT_EV_EXT_ADV_SID_CHANGED            0x0033
> +struct mgmt_ev_ext_adv_sid_changed {
> +       struct mgmt_addr_info addr;
> +       __u8    sid;
> +} __packed;

I rather have a new device found event, or somehow embed the SID into
the existing one.

> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index 467710a42d45..f4463e71b424 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -6519,6 +6519,9 @@ static void hci_le_ext_adv_report_evt(struct hci_dev *hdev, void *data,
>                                            info->rssi, info->data, info->length,
>                                            !(evt_type & LE_EXT_ADV_LEGACY_PDU),
>                                            false, instant);
> +                       mgmt_ext_adv_sid_changed(hdev, &info->bdaddr,
> +                                                     info->bdaddr_type,
> +                                                     info->sid);
>                 }
>         }
>
> diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
> index 5be9b8c91949..4e0f8c43e387 100644
> --- a/net/bluetooth/mgmt.c
> +++ b/net/bluetooth/mgmt.c
> @@ -208,6 +208,7 @@ static const u16 mgmt_untrusted_events[] = {
>         MGMT_EV_EXT_INDEX_REMOVED,
>         MGMT_EV_EXT_INFO_CHANGED,
>         MGMT_EV_EXP_FEATURE_CHANGED,
> +       MGMT_EV_EXT_ADV_SID_CHANGED,
>  };
>
>  #define CACHE_TIMEOUT  secs_to_jiffies(2)
> @@ -10516,6 +10517,18 @@ void mgmt_device_found(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>         mgmt_adv_monitor_device_found(hdev, bdaddr, report_device, skb, NULL);
>  }
>
> +void mgmt_ext_adv_sid_changed(struct hci_dev *hdev, bdaddr_t *bdaddr,
> +                                    u8 addr_type, u8 sid)
> +{
> +       struct mgmt_ev_ext_adv_sid_changed ev;
> +
> +       bacpy(&ev.addr.bdaddr, bdaddr);
> +       ev.addr.type = link_to_bdaddr(LE_LINK, addr_type);
> +       ev.sid = sid;
> +
> +       mgmt_event(MGMT_EV_EXT_ADV_SID_CHANGED, hdev, &ev, sizeof(ev), NULL);
> +}
> +
>  void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
>                       u8 addr_type, s8 rssi, u8 *name, u8 name_len)
>  {
>
> ---
> base-commit: 030d2c0e9c1d68e67f91c08704482ad9881583eb
> change-id: 20260107-mgmt_ext_adv_sid-7ea503e46791
>
> Best regards,
> --
> Yang Li <yang.li@xxxxxxxxxxx>
>
>


-- 
Luiz Augusto von Dentz