Hi,
[ EXTERNAL EMAIL ]
Hi,
pe, 2025-07-04 kello 13:36 +0800, Yang Li via B4 Relay kirjoitti:
From: Yang Li <yang.li@xxxxxxxxxxx>
User-space applications (e.g., PipeWire) depend on
ISO-formatted timestamps for precise audio sync.
Signed-off-by: Yang Li <yang.li@xxxxxxxxxxx>
---
Changes in v3:
- Change to use hwtimestamp
- Link to v2: https://lore.kernel.org/r/20250702-iso_ts-v2-1-723d199c8068@xxxxxxxxxxx
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@xxxxxxxxxxx
---
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);
+ if (hwts)
In addition to the moving variable on top, the null check is spurious
as skb_hwtstamps is never NULL (driver/net/* do not check it either).
Did you test this with SOF_TIMESTAMPING_RX_HARDWARE in userspace?
Pipewire does not try to get HW timestamps right now.
Would be good to also add some tests in bluez/tools/iso-tester.c
although this needs some extension to the emulator/* to support
timestamps properly.
Yes, here is the patch and log based on testing with Pipewire:
diff --git a/spa/plugins/bluez5/media-source.c
b/spa/plugins/bluez5/media-source.c
index 2fe08b8..10e9378 100644
--- a/spa/plugins/bluez5/media-source.c
+++ b/spa/plugins/bluez5/media-source.c
@@ -407,7 +413,7 @@ static int32_t read_data(struct impl *this) {
struct msghdr msg = {0};
struct iovec iov;
char control[128];
- struct timespec *ts = NULL;
+ struct scm_timestamping *ts = NULL;
iov.iov_base = this->buffer_read;
iov.iov_len = b_size;
@@ -439,12 +445,14 @@ again:
struct cmsghdr *cmsg;
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL; cmsg =
CMSG_NXTHDR(&msg, cmsg)) {
#ifdef SCM_TIMESTAMPING
/* Check for timestamp */
+ if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type ==
SCM_TIMESTAMPING) {
+ ts = (struct scm_timestamping *)CMSG_DATA(cmsg);
+ spa_log_error(this->log, "%p: received timestamp
%ld.%09ld",
+ this, ts->ts[2].tv_sec,
ts->ts[2].tv_nsec);
break;
}
#endif
@@ -726,9 +734,9 @@ static int transport_start(struct impl *this)
if (setsockopt(this->fd, SOL_SOCKET, SO_PRIORITY, &val,
sizeof(val)) < 0)
spa_log_warn(this->log, "SO_PRIORITY failed: %m");
+ val = SOF_TIMESTAMPING_RX_HARDWARE | SOF_TIMESTAMPING_RAW_HARDWARE;
+ if (setsockopt(this->fd, SOL_SOCKET, SO_TIMESTAMPING, &val,
sizeof(val)) < 0) {
+ spa_log_warn(this->log, "SO_TIMESTAMPING failed: %m");
/* don't fail if timestamping is not supported */
}
trace log：
read_data: 0x1e78d68: received timestamp 7681.972000000
read_data: 0x1e95000: received timestamp 7681.972000000
read_data: 0x1e78d68: received timestamp 7691.972000000
read_data: 0x1e95000: received timestamp 7691.972000000
read_data: 0x1e78d68: received timestamp 7701.972000000
read_data: 0x1e95000: received timestamp 7701.972000000
read_data: 0x1e78d68: received timestamp 7711.972000000
read_data: 0x1e95000: received timestamp 7711.972000000
read_data: 0x1e78d68: received timestamp 7721.972000000
read_data: 0x1e95000: received timestamp 7721.972000000
read_data: 0x1e78d68: received timestamp 7731.972000000
+ 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,
--
Pauli Virtanen
