Re: [PATCH] Bluetooth: ISO: add timestamp for outgoing HCI ISO packet

[Tailu Shi]

Hi Paul,

Thank you for the review and the helpful suggestion about my name.

I have updated my Git configuration and amended the commit as you advised:

    git config --global user.name "Tailu Shi"
    git commit --amend -s --author="Tailu Shi <tailu.shi@xxxxxxxxxxx>"


On Wed, 11 Mar 2026 09:54:38 +0100 Paul Menzel wrote:
>> A corresponding userspace change is required for full functionality.
>> A reference implementation is available in PipeWire:
>> https://gitlab.freedesktop.org/shitailu/pipewire/-/commit/5b3bd74e15febb974c8737a64f31fd17e18cd11b
> 
> Is the timestamp correctly visible in the btmon trace?

Yes, it can be seen in the btmon trace. The test was performed on the
kernel 7.0.0‑rc1+, using BlueZ 5.85 and PipeWire 1.5.84 with the
'bluez5.iso-tx-timestamp' configuration option enabled.

But seems the btmon v5.85 and v5.86 fails to parse it directly with
the command. However, the 'ts' field can be seen clearly with Wireshark.

The things are like below:

1) btmon v5.86
 $ btmon -r dump.btsnoop -I |grep -A1 'ISO Data TX: Handle 2563'
 < ISO Data TX: Handle 2563 [5/18] SN 2                 #10999 [hci0] 128.571172
         02 00 3c 00 00 00 00 00 00 00 00 00 00 00 00 00  ..<.............
 --

2) Wireshark
 Frame 19604: 72 bytes on wire (576 bits), 72 bytes captured (576 bits)
 Bluetooth
 Bluetooth Linux Monitor Transport
 Bluetooth HCI ISO Packet
     .... 1010 0000 0011 = Connection Handle: 0xa03
     ..10 .... .... .... = PB Flag: Complete SDU (0x2)
     .1.. .... .... .... = Timestamp present: True
     0... .... .... .... = Reserved: 0x0
     ..00 0000 0100 0100 = Data Length: 68
     Data
     [Connect in frame: 18836]
 Bluetooth ISO Data
     Timestamp: 805103660µs
     Sequence Number: 84
     .... 0000 0011 1100 = SDU Length: 60
     SDU

Raw data:
 0000   03 6a 44 00 2c e8 fc 2f 54 00 3c 00 00 00 00 00   .jD.,../T.<.....
 0010   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
 0020   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
 0030   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
 0040   38 24 f9 4a 0d 00 00 03                           8$.J....


Thanks for your time again!

Best regards,

Tailu Shi