Re: [net-next, v5, 08/11] net: sock: extend SO_TIMESTAMPING for PHC binding

[Richard Cochran]

On Wed, Jun 30, 2021 at 04:11:59PM +0800, Yangbo Lu wrote:
> Since PTP virtual clock support is added, there can be
> several PTP virtual clocks based on one PTP physical
> clock for timestamping.
> 
> This patch is to extend SO_TIMESTAMPING API to support
> PHC (PTP Hardware Clock) binding by adding a new flag
> SOF_TIMESTAMPING_BIND_PHC. When PTP virtual clocks are
> in use, user space can configure to bind one for
> timestamping, but PTP physical clock is not supported
> and not needed to bind.

Would it not be better to simply bind automatically?

Like this pseudo code:

	if (hw_timestamping_requested() && interface_is_vclock()) {
		bind_vclock();
	}

It would be great to avoid forcing user space to use a new option.

Especially because NOT setting the option makes no sense.  Or maybe
there is a use case for omitting the option?


Thoughts?

Thanks,
Richard