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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Mon, 30 Oct 2023 08:39:26 +0100
Message-ID: <CACRpkdZXAqkn0QeX4s2JFmyMOz82uQq7C18408Kow-peN8tCqA@mail.gmail.com>
Subject: Re: [PATCH] dsa: tag_rtl4_a: Bump min packet size
To:     Andrew Lunn <andrew@lunn.ch>
Cc:     Vladimir Oltean <olteanv@gmail.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Mauri Sandberg <sandberg@mailfence.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Mon, Oct 30, 2023 at 12:00=E2=80=AFAM Andrew Lunn <andrew@lunn.ch> wrote=
:

> > 1496 is suspiciously much 1500 - DSA tag size. However the
> > MTU of the parent ethernet is bumped nicely to 1504 and the
> > device MTU is set up to accomodate it as well.
> >
> > Modifying the patch to just pad out packets >=3D 1496 bytes
> > solves the problem in a better way, but maybe that is not the
> > last thing we try here...
>
> Have you tried playing with RTL8366RB_SGCR in rtl8366rb_change_mtu()?

Yes I set the MTU to increasingly larger sizes.

Sadly MTU has nothing to do with this, it's really annoying,
I have a v2 patch that is better and working, I'll include some test
text so you see where the problem is.

Yours,
Linus Walleij