Re: [PATCH v3] Bluetooth: ISO: Support SCM_TIMESTAMPING for ISO TS

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

Hi,
> [ EXTERNAL EMAIL ]
>
> On Fri, 2025-07-04 at 13:36 +0800, Yang Li via B4 Relay wrote:
>> From: Yang Li <yang.li@amlogic.com>
>>
>> User-space applications (e.g., PipeWire) depend on
>> ISO-formatted timestamps for precise audio sync.
>>
>> Signed-off-by: Yang Li <yang.li@amlogic.com>
>> ---
>> Changes in v3:
>> - Change to use hwtimestamp
>> - Link to v2:
>> https://lore.kernel.org/r/20250702-iso_ts-v2-1-723d199c8068@amlogic.com
>>
>> Changes in v2:
>> - Support SOCK_RCVTSTAMPNS via CMSG for ISO sockets
>> - Link to v1:
>> https://lore.kernel.org/r/20250429-iso_ts-v1-1-e586f30de6cb@amlogic.com
>> ---
>>   net/bluetooth/iso.c | 10 +++++++++-
>>   1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
>> index fc22782cbeeb..67ff355167d8 100644
>> --- a/net/bluetooth/iso.c
>> +++ b/net/bluetooth/iso.c
>> @@ -2301,13 +2301,21 @@ void iso_recv(struct hci_conn *hcon, struct
>> sk_buff *skb, u16 flags)
>>                if (ts) {
>>                        struct hci_iso_ts_data_hdr *hdr;
>>
>> -                     /* TODO: add timestamp to the packet? */
>>                        hdr = skb_pull_data(skb,
>> HCI_ISO_TS_DATA_HDR_SIZE);
>>                        if (!hdr) {
>>                                BT_ERR("Frame is too short (len
>> %d)", skb->len);
>>                                goto drop;
>>                        }
>>
>> +                     /* The ISO ts is based on the controller’s
>> clock domain,
>> +                      * so hardware timestamping (hwtimestamp)
>> must be used.
>> +                      * Ref:
>> Documentation/networking/timestamping.rst,
>> +                      * chapter 3.1 Hardware Timestamping.
>> +                      */
>> +                     struct skb_shared_hwtstamps *hwts =
>> skb_hwtstamps(skb);
> The variable should be declared at the top of the scope.
>
> Cheers


Will do.

>> +                     if (hwts)
>> +                             hwts->hwtstamp =
>> us_to_ktime(le32_to_cpu(hdr->ts));
>> +
>>                        len = __le16_to_cpu(hdr->slen);
>>                } else {
>>                        struct hci_iso_data_hdr *hdr;
>>
>> ---
>> base-commit: 3bc46213b81278f3a9df0324768e152de71eb9fe
>> change-id: 20250421-iso_ts-c82a300ae784
>>
>> Best regards,