Re: [PATCH net-next v2 1/8] net-timestamp: explicit SO_TIMESTAMPING ancillary data struct

[Willem de Bruijn <willemb@google.com>]

On Mon, Jul 7, 2014 at 2:47 PM, Richard Cochran
<richardcochran@gmail.com> wrote:
> On Mon, Jul 07, 2014 at 11:34:05AM -0400, Willem de Bruijn wrote:
>>
>> The hardware timestamp converted to system time is deprecated? I did
>> not know that. Because it is largely unused, or for a more fundamental
>> reason?
>
> It is for the fundamental reason that the idea behind it is just plain
> wrong. MAC drivers are not the place to put clock servos.
>
>> If so, the documentation could indeed use an explicit comment. The
>> definition of skb_shared_hwtstamps.syststamp too. I can write a small
>> patch independent of this patchset.
>
> Please do.

Ok. See below.

>
>> Unfortunately, a cursory inspection shows one, octeon. While that user
>> exists and generates such timestamps, I think that the above new flag
>> should be passed, as well, for API consistency.
>
> Ugh, how the heck did that turd get in? Its not like they bothered to
> include the maintainer on CC. That code must go.

I'm happy to unwind the syststamp part of 3d305850 ("netdev:
octeon_mgmt: Add hardware timestamp support"). Chad, let me know if
you object to that. Else, I'll send a patch to you both for review.

Once that is in, I'll follow up with a driver-independent stack patch
that removes the field in internal struct skb_shared_hwtstamps and
documents the legacy nature of the field in scm_timestamping. In
that case, we don't have to document the internal field in the interim.

>
> Thanks,
> Richard