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From:   Matteo Croce <mcroce@redhat.com>
Date:   Sun, 28 Jul 2019 03:36:31 +0200
Message-ID: <CAGnkfhycOc8mvqeQDBcnXueUjrFQMC7hdfAOkxr5k0+xc_tnDw@mail.gmail.com>
Subject: Re: [PATCH net-next] mvpp2: document HW checksum behaviour
To:     Antoine Tenart <antoine.tenart@bootlin.com>,
        Marcin Wojtas <mw@semihalf.com>,
        Stefan Chulski <stefanc@marvell.com>,
        Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc:     netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "David S . Miller" <davem@davemloft.net>
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On Fri, Jul 26, 2019 at 2:57 PM Antoine Tenart
<antoine.tenart@bootlin.com> wrote:
>
> Hi Matteo,
>
> On Fri, Jul 26, 2019 at 01:15:46AM +0200, Matteo Croce wrote:
> > The hardware can only offload checksum calculation on first port due to
> > the Tx FIFO size limitation. Document this in a comment.
> >
> > Fixes: 576193f2d579 ("net: mvpp2: jumbo frames support")
> > Signed-off-by: Matteo Croce <mcroce@redhat.com>
>
> Looks good. Please note there's a similar code path in the probe. You
> could also add a comment there (or move this check/comment in a common
> place).
>
> Thanks!
> Antoine
>

Hi Antoine,

I was making a v2, when I looked at the mvpp2_port_probe() which does:

--------------------------------%<------------------------------
features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM | NETIF_F_TSO;

if (port->pool_long->id == MVPP2_BM_JUMBO && port->id != 0) {
    dev->features &= ~(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
    dev->hw_features &= ~(NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM);
}

dev->vlan_features |= features;
-------------------------------->%------------------------------

Is it ok to remove NETIF_F_IP*_CSUM from dev->features and
dev->hw_features but keep it in dev->vlan_features?

Regards,
-- 
Matteo Croce
per aspera ad upstream