Re: [PATCH v3] Bluetooth: hci_event: Add support for handling LE BIG Sync Lost event

[Yang Li]

Hi Luzi,
> [ EXTERNAL EMAIL ]
>
> Hi,
>
> On Mon, Jun 30, 2025 at 2:45 AM Yang Li via B4 Relay
> <devnull+yang.li.amlogic.com@xxxxxxxxxx> wrote:
> > From: Yang Li <yang.li@xxxxxxxxxxx>
> >
> > When the BIS source stops, the controller sends an LE BIG Sync Lost
> > event (subevent 0x1E). Currently, this event is not handled, causing
> > the BIS stream to remain active in BlueZ and preventing recovery.
> >
> > Signed-off-by: Yang Li <yang.li@xxxxxxxxxxx>
> > ---
> > Changes in v3:
> > - Delete the PA sync connection separately.
> > - Add state and role check when lookup BIS connections
> > - Link to v2: https://lore.kernel.org/r/20250625-handle_big_sync_lost_event-v2-1-81f163057a21@xxxxxxxxxxx
> >
> > Changes in v2:
> > - Matching the BIG handle is required when looking up a BIG connection.
> > - Use ev->reason to determine the cause of disconnection.
> > - Call hci_conn_del after hci_disconnect_cfm to remove the connection entry
> > - Delete the big connection
> > - Link to v1: https://lore.kernel.org/r/20250624-handle_big_sync_lost_event-v1-1-c32ce37dd6a5@xxxxxxxxxxx
> > ---
> >   include/net/bluetooth/hci.h      |  6 ++++++
> >   include/net/bluetooth/hci_core.h | 16 ++++++++++++----
> >   net/bluetooth/hci_conn.c         |  3 ++-
> >   net/bluetooth/hci_event.c        | 39 ++++++++++++++++++++++++++++++++++++++-
> >   4 files changed, 58 insertions(+), 6 deletions(-)
> >
> > diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> > index 82cbd54443ac..48389a64accb 100644
> > --- a/include/net/bluetooth/hci.h
> > +++ b/include/net/bluetooth/hci.h
> > @@ -2849,6 +2849,12 @@ struct hci_evt_le_big_sync_estabilished {
> >          __le16  bis[];
> >   } __packed;
> >
> > +#define HCI_EVT_LE_BIG_SYNC_LOST 0x1e
> > +struct hci_evt_le_big_sync_lost {
> > +       __u8    handle;
> > +       __u8    reason;
> > +} __packed;
> > +
> >   #define HCI_EVT_LE_BIG_INFO_ADV_REPORT 0x22
> >   struct hci_evt_le_big_info_adv_report {
> >          __le16  sync_handle;
> > diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> > index a760f05fa3fb..5ab19d4fef93 100644
> > --- a/include/net/bluetooth/hci_core.h
> > +++ b/include/net/bluetooth/hci_core.h
> > @@ -1340,7 +1340,8 @@ hci_conn_hash_lookup_big_sync_pend(struct hci_dev *hdev,
> >   }
> >
> >   static inline struct hci_conn *
> > -hci_conn_hash_lookup_big_state(struct hci_dev *hdev, __u8 handle,  __u16 state)
> > +hci_conn_hash_lookup_big_state(struct hci_dev *hdev, __u8 handle,
> > +                              __u16 state, __u8 role)
> >   {
> >          struct hci_conn_hash *h = &hdev->conn_hash;
> >          struct hci_conn  *c;
> > @@ -1348,9 +1349,16 @@ hci_conn_hash_lookup_big_state(struct hci_dev *hdev, __u8 handle,  __u16 state)
> >          rcu_read_lock();
> >
> >          list_for_each_entry_rcu(c, &h->list, list) {
> > -               if (c->type != BIS_LINK || bacmp(&c->dst, BDADDR_ANY) ||
> > -                   c->state != state)
> > -                       continue;
> > +               if (role == HCI_ROLE_MASTER) {
> > +                       if (c->type != BIS_LINK || bacmp(&c->dst, BDADDR_ANY) ||
> > +                               c->state != state || c->role != role)
> > +                               continue;
> We don't really need to compare the address anymore since we now have
> dedicated types for CIS and BIS, Id probably fix that in a leading
> patch since that should have been added as a Fixes to the commit that
> introduced the separate types, I will send a fix for it just make sure
> you rebase your tree on top of bluetooth-next.
>
> > +               } else {
> > +                       if (c->type != BIS_LINK ||
> > +                               c->state != state ||
> > +                               c->role != role)
> > +                               continue;
> > +               }
> Then all we need to do is add the role check.


Yes, I will do.

> >                  if (handle == c->iso_qos.bcast.big) {
> >                          rcu_read_unlock();
> > diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
> > index 4f379184df5b..6bb1ab42db39 100644
> > --- a/net/bluetooth/hci_conn.c
> > +++ b/net/bluetooth/hci_conn.c
> > @@ -2146,7 +2146,8 @@ struct hci_conn *hci_bind_bis(struct hci_dev *hdev, bdaddr_t *dst, __u8 sid,
> >          struct hci_link *link;
> >
> >          /* Look for any BIS that is open for rebinding */
> > -       conn = hci_conn_hash_lookup_big_state(hdev, qos->bcast.big, BT_OPEN);
> > +       conn = hci_conn_hash_lookup_big_state(hdev, qos->bcast.big,
> > +                                            BT_OPEN, HCI_ROLE_MASTER);
> >          if (conn) {
> >                  memcpy(qos, &conn->iso_qos, sizeof(*qos));
> >                  conn->state = BT_CONNECTED;
> > diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> > index 66052d6aaa1d..f3e3e4964677 100644
> > --- a/net/bluetooth/hci_event.c
> > +++ b/net/bluetooth/hci_event.c
> > @@ -3903,6 +3903,8 @@ static u8 hci_cc_le_setup_iso_path(struct hci_dev *hdev, void *data,
> >                  goto unlock;
> >          }
> >
> > +       conn->state = BT_CONNECTED;
> > +
> >          switch (cp->direction) {
> >          /* Input (Host to Controller) */
> >          case 0x00:
> > @@ -6913,7 +6915,7 @@ static void hci_le_create_big_complete_evt(struct hci_dev *hdev, void *data,
> >
> >          /* Connect all BISes that are bound to the BIG */
> >          while ((conn = hci_conn_hash_lookup_big_state(hdev, ev->handle,
> > -                                                     BT_BOUND))) {
> > +                                       BT_BOUND, HCI_ROLE_MASTER))) {
> >                  if (ev->status) {
> >                          hci_connect_cfm(conn, ev->status);
> >                          hci_conn_del(conn);
> > @@ -6968,6 +6970,7 @@ static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
> >          }
> >
> >          clear_bit(HCI_CONN_CREATE_BIG_SYNC, &conn->flags);
> > +       conn->state = BT_CONNECTED;
> Wrong line, anyway I have fixed this upstream already so you need to rebase.
Got it.
> >          conn->num_bis = 0;
> >          memset(conn->bis, 0, sizeof(conn->num_bis));
> > @@ -7026,6 +7029,35 @@ static void hci_le_big_sync_established_evt(struct hci_dev *hdev, void *data,
> >          hci_dev_unlock(hdev);
> >   }
> >
> > +static void hci_le_big_sync_lost_evt(struct hci_dev *hdev, void *data,
> > +                                    struct sk_buff *skb)
> > +{
> > +       struct hci_evt_le_big_sync_lost *ev = data;
> > +       struct hci_conn *bis, *conn;
> > +
> > +       bt_dev_dbg(hdev, "big handle 0x%2.2x", ev->handle);
> > +
> > +       hci_dev_lock(hdev);
> > +
> > +       /* Delete the pa sync connection */
> > +       bis = hci_conn_hash_lookup_pa_sync_big_handle(hdev, ev->handle);
> > +       if (bis) {
> > +               conn = hci_conn_hash_lookup_pa_sync_handle(hdev, bis->sync_handle);
> > +               if (conn)
> > +                       hci_conn_del(conn);
> > +       }
> > +
> > +       /* Delete each bis connection */
> > +       while ((bis = hci_conn_hash_lookup_big_state(hdev, ev->handle,
> > +                                               BT_CONNECTED, HCI_ROLE_SLAVE))) {
> > +               clear_bit(HCI_CONN_BIG_SYNC, &bis->flags);
> > +               hci_disconn_cfm(bis, ev->reason);
> > +               hci_conn_del(bis);
> > +       }
> > +
> > +       hci_dev_unlock(hdev);
> > +}
> > +
> >   static void hci_le_big_info_adv_report_evt(struct hci_dev *hdev, void *data,
> >                                             struct sk_buff *skb)
> >   {
> > @@ -7149,6 +7181,11 @@ static const struct hci_le_ev {
> >                       hci_le_big_sync_established_evt,
> >                       sizeof(struct hci_evt_le_big_sync_estabilished),
> >                       HCI_MAX_EVENT_SIZE),
> > +       /* [0x1e = HCI_EVT_LE_BIG_SYNC_LOST] */
> > +       HCI_LE_EV_VL(HCI_EVT_LE_BIG_SYNC_LOST,
> > +                    hci_le_big_sync_lost_evt,
> > +                    sizeof(struct hci_evt_le_big_sync_lost),
> > +                    HCI_MAX_EVENT_SIZE),
> After you fix the comments I do expect some code to introduce support
> into our emulator and then add some test to iso-tester that causes the
> test to generate HCI_EVT_LE_BIG_SYNC_LOST so we can confirm this is
> working as intended.


Sure, I'll give it a try.

> >          /* [0x22 = HCI_EVT_LE_BIG_INFO_ADV_REPORT] */
> >          HCI_LE_EV_VL(HCI_EVT_LE_BIG_INFO_ADV_REPORT,
> >                       hci_le_big_info_adv_report_evt,
> >
> > ---
> > base-commit: bd35cd12d915bc410c721ba28afcada16f0ebd16
> > change-id: 20250612-handle_big_sync_lost_event-4c7dc64390a2
> >
> > Best regards,
> > --
> > Yang Li <yang.li@xxxxxxxxxxx>
>
> --
> Luiz Augusto von Dentz