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Date:   Fri, 9 Dec 2022 15:54:36 +0100
From:   Horatiu Vultur <horatiu.vultur@microchip.com>
To:     Michael Walle <michael@walle.cc>
CC:     Vladimir Oltean <olteanv@gmail.com>,
        <Steen.Hegelund@microchip.com>, <UNGLinuxDriver@microchip.com>,
        <daniel.machon@microchip.com>, <davem@davemloft.net>,
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        <lars.povlsen@microchip.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
        <pabeni@redhat.com>, <richardcochran@gmail.com>
Subject: Re: [PATCH net-next v3 4/4] net: lan966x: Add ptp trap rules
Message-ID: <20221209145436.o5nclzrtu2eztvzs@soft-dev3-1>
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The 12/09/2022 15:23, Michael Walle wrote:
> 
> Am 2022-12-09 15:20, schrieb Horatiu Vultur:
> > The 12/09/2022 15:05, Michael Walle wrote:
> > > 
> > > Am 2022-12-09 13:56, schrieb Vladimir Oltean:
> > > > On Fri, Dec 09, 2022 at 01:58:57PM +0100, Horatiu Vultur wrote:
> > > > > > Does it also work out of the box with the following patch if
> > > > > > the interface is part of a bridge or do you still have to do
> > > > > > the tc magic from above?
> > > > >
> > > > > You will still need to enable the TCAM using the tc command to have it
> > > > > working when the interface is part of the bridge.
> > > >
> > > > FWIW, with ocelot (same VCAP mechanism), PTP traps work out of the box,
> > > > no need to use tc. Same goes for ocelot-8021q, which also uses the
> > > > VCAP.
> > > > I wouldn't consider forcing the user to add any tc command in order for
> > > > packet timestamping to work properly.
> > 
> > On ocelot, the vcap is enabled at port initialization, while on other
> > platforms(lan966x and sparx5) you have the option to enable or disable.
> > 
> > > 
> > > +1
> > > Esp. because there is no warning. I.e. I tried this patch while
> > > the interface was added on a bridge and there was no error
> > > whatsoever.
> > 
> > What error/warning were you expecting to see here?
> 
> Scrap that. ptp4l is reporting an error in case the device is part
> of a bridge:
> Jan  1 02:33:04 buildroot user.info syslog: [9184.261] driver rejected
> most general HWTSTAMP filter
> 
> Nevertheless, from a users POV I'd just expect it to work. How
> would I know what I need to do here?

What about a warning in the driver? Say that the vcap needs to be
enabled.

> 
> -michael

-- 
/Horatiu