Re: [Linuxptp-devel] [RFC 1/1] Add avnu_ap to enable AVnu Automotive Profile

[Patel, V. <ved...@in...>]

On Thu, 2018-07-19 at 21:21 +0000, Patel, Vedang wrote:
> Thanks for your inputs Richard. I will rework the patch as you
> suggested. Some comments/questions for the patch inline.
> 
> On Thu, 2018-07-19 at 08:01 -0700, Richard Cochran wrote:
> > 
> > On Mon, Jul 16, 2018 at 02:34:47PM -0700, Vedang Patel wrote:
> > > 
> > > 
> > > This adds a new config option "avnu_ap" for ptp4l. Setting this
> > > option
> > > to 1 will enable the AVnu Automotive Profile (AVnu AP) [1] for
> > > the
> > > device.
> > This is not how we do things.
> > 
> > I have said this more than once before.  We don't add a single
> > monolithic Boolean option for some random profile or extension.
> > 
> > Instead, for each different behavior or attribute, we add a
> > granular
> > option.  Then, the profile is simply a configuration file selecting
> > the appropriate options. 
> > 
> Ok. Will split this patch out into different options. Will send a
> follow-up email on what I think the best options are.

So, following is what we think will do the job:
- Add inhibit_announce option to stop announce messages as well as
timeouts. (default: 0 - disabled)
- Add source_port_identity_check option to disable checking for source
port identities in sync and follow-up messages (default: 1 - enabled)
- Add static_roles config which is a tristate - master, slave and
disabled. When master or slave roles are selected, the FSM will
directly assign those roles. (default: 'disabled')

Following are the configs needed for each role:
master: static_role = 'master', inhibit_announce = 1
slave: static_role = 'slave', source_port_identity_check = 0

We also looked into the slaveOnly FSM for slave. But, we cannot use
that because it still expects the announce message from the master
before transitioning to UNCALIBRATED state.

We also looked into using masterOnly option. But, it will wait for
announce receipt timeout before transitioning to MASTER. But,
inhibit_announce will disable that.

Let us know if this meets your expectations. 

Thanks,
Vedang Patel