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From:   Sven Van Asbroeck <thesven73@gmail.com>
Date:   Thu, 8 Apr 2021 14:26:09 -0400
Message-ID: <CAGngYiU=v16Z3NHC0FyxcZqEJejKz5wn2hjLubQZKJKHg_qYhw@mail.gmail.com>
Subject: Re: [PATCH net v1] Revert "lan743x: trim all 4 bytes of the FCS; not
 just 2"
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     George McCollister <george.mccollister@gmail.com>,
        Bryan Whitehead <bryan.whitehead@microchip.com>,
        David S Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
        netdev <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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Hi Heiner,

On Thu, Apr 8, 2021 at 2:22 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> Just an idea:
> RX_HEAD_PADDING is an alias for NET_IP_ALIGN that can have two values:
> 0 and 2
> The two systems you use may have different NET_IP_ALIGN values.
> This could explain the behavior. Then what I proposed should work
> for both of you: frame_length - ETH_FCS_LEN

Yes, good point! I was thinking the exact same thing just now.
Subtracting 2 + RX_HEAD_PADDING from the frame length made no sense.

George, I will send a patch for you to try shortly. Except if you're
already ahead :)