Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38;
Date:   Mon, 30 Oct 2023 00:00:46 +0100
From:   Andrew Lunn <andrew@lunn.ch>
To:     Linus Walleij <linus.walleij@linaro.org>
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
Subject: Re: [PATCH] dsa: tag_rtl4_a: Bump min packet size
Message-ID: <54f8d583-e900-4ce8-87d1-a18556698f10@lunn.ch>
References: <20231027-fix-rtl8366rb-v1-1-d565d905535a@linaro.org>
 <20231028220402.gdsynephzfkpvk4m@skbuf>
 <CACRpkdbq03ZXcB-TaBp5Udo3M47rb-o+LfkEkC-gA1+=x1Zd-g@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CACRpkdbq03ZXcB-TaBp5Udo3M47rb-o+LfkEkC-gA1+=x1Zd-g@mail.gmail.com>
Precedence: bulk

> 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 >= 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()?

I had an annoying bug in the mv88e6xxx driver where the MTU
configuration register was up to, but not including... So i had to
change a <= to <.

	Andrew