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

[Yang Li <yang.li@amlogic.com>]

Hi,
> [ EXTERNAL EMAIL ]
>
> Dear Li,
>
>
> Thank you for your patch.
>
>
> Am 24.06.25 um 07:20 schrieb Yang Li via B4 Relay:
>> From: Yang Li <yang.li@amlogic.com>
>>
>> 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.
>
> How can this situation be emulated to test your patch?


My test environment is as follows:

I connect a Pixel phone to the DUT and use the phone as a BIS source for 
audio sharing. The DUT synchronizes with the audio stream from the phone.
After I pause the music on the phone, the DUT's controller reports a BIG 
Sync Lost event.

I believe this scenario can also be reproduced using the isotest tool. 
For example:
  - Use Board A as the BIS source.
  - Use Board B to execute scan on.
  - Once Board B synchronizes with Board A, exit isotest on Board A.
  - Board B should then receive the BIG Sync Lost event as well.

Additionally, the following BlueZ patch is required for proper handling 
of this event:
https://lore.kernel.org/all/20250624-bap_for_big_sync_lost-v1-1-0df90a0f55d0@amlogic.com/


>
>> Signed-off-by: Yang Li <yang.li@amlogic.com>
>> ---
>>   include/net/bluetooth/hci.h |  6 ++++++
>>   net/bluetooth/hci_event.c   | 23 +++++++++++++++++++++++
>>   2 files changed, 29 insertions(+)
>>
>> 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/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
>> index 66052d6aaa1d..730deaf1851f 100644
>> --- a/net/bluetooth/hci_event.c
>> +++ b/net/bluetooth/hci_event.c
>> @@ -7026,6 +7026,24 @@ 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 *conn;
>> +
>> +     bt_dev_dbg(hdev, "BIG Sync Lost: big_handle 0x%2.2x", ev->handle);
>> +
>> +     hci_dev_lock(hdev);
>> +
>> +     list_for_each_entry(conn, &hdev->conn_hash.list, list) {
>> +             if (test_bit(HCI_CONN_BIG_SYNC, &conn->flags))
>> +                     hci_disconn_cfm(conn, HCI_ERROR_REMOTE_USER_TERM);
>> +     }
>> +
>> +     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 +7167,11 @@ 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),
>>       /* [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,
>
> Kind regards,
>
> Paul