Re: [PATCH net-next v2 0/8] Add support for two classes of VCAP rules

[Steen Hegelund <steen.hegelund@microchip.com>]

Hi Michael,

On Fri, 2023-01-06 at 11:46 +0100, Michael Walle wrote:
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> 
> Hi,
> 
> > > Wouldn't it make more sense, to fix the regression via net (and
> > > a Fixes: tag) and then make that stuff work without tc? Maybe
> > > the fix is just reverting the commits.
> > 
> > I have discussed this again with Horatiu and I have the following
> > suggestion of
> > how to proceed:
> > 
> > 1) Create a small LAN966x specific patch for net (see below for the two
> > possible
> >    variants).
> > 
> > 2) Continue with a net-next V3 without any 'Fixes' tags on top of the
> > patch in
> >    (1) when it becomes available in net-next.
> 
> Sounds good.
> 
> [coming back to this after writing the response below, so see there
> for more context]
> When do the patches from net become available in net-next? Only after a
> merge window? If so, depending on the solution for (1) you'd have two
> "in-between" kernel versions (v6.2 and v6.3).

According to our own experience the changes in net are usually merged into net-
next the following Thursday: so not too much delay, before we can continue.

> 
> > The LAN966x patch for net (with a Fixes tag) could contain either:
> > 
> > a) No check on enabled lookup
> > 
> >    Removal of the check for enabled lookups:
> > 
> >    -  if (!ANA_VCAP_S2_CFG_ENA_GET(val))
> >    -          return -ENOENT;
> > 
> >    This will remove the error that you have seen, but  will still
> > require a
> >    matchall rule to enable the PTP rules.  This is compatible with the
> > TC
> >    framework.
> > 
> > b) Always enable lookups
> > 
> >    Enable the lookups at startup.
> >    Remove the lookup enable check as above.
> > 
> >    This will make the PTP rules (and any other rules) work even without
> > the
> >    matchall rule to enable them.  It its not ideal, but solves the
> > problem that
> >    you have been experiencing without the 'TC magic'
> > 
> >    The V3 in net-next will provide the full solution.
> > 
> > I expect that you might prefer the b) version.
> 
> I *assume* linuxptp would have worked in my case (no bridge interface)
> before Horatiu patches. As mentioned before, I haven't really tested it.
> Does that mean with a) the error is gone and linuxptp is working as
> before? If so, I'm also fine with a).

Yes this is the result: So I also suggest to go for solution a).

This will still allow LinuxPTP to work (without the error that you have seen),
but the bridged interface PTP support must be enabled with a TC matchall rule.

> 
> Honestly, now that there is a good solution in future kernels, I
> don't care toooo much about that one particular kernel. Other
> users might disagree though ;)
> 
> I just want to point out that right now you have some kind of
> in-between kernel with 6.2:
> 
>   <=6.1 linuxptp working (but not on bridged ports)
>   6.2   linuxptp working only with tc magic
>   6.3   linuxptp working

So with the LAN966x patch the second line would change to:

6.2   linuxptp working. PTP on bridged interfaces: needs TC matchall rule

> 
> Therefore, I've raised the question if it's also viable to just
> revert the former changes for 6.2. The you'd have a clean
> transition.
> 
> -michael

TLDR Summary:

1) LAN966x patch for net to ensure PTP is working without errors
2) A V3 net-next VCAP series with the improvements for enabled/disable/permanent
rules (both LAN966x and Sparx5)

I will move forward with this.

BR
Steen


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