Re: [PATCH] rtase: Workaround for IP fragmented UDP packet hardware bug

[Andrew Lunn]

On Mon, Jun 01, 2026 at 02:23:41PM +0800, Justin Lai wrote:
> The hardware parser incorrectly interprets 319/320 in a short
> IP fragmented UDP packet payload as standard PTP destination
> ports and treats the fragment as a PTP packet for further
> parsing.
> 
> If the transport data is smaller than RTASE_MIN_PAD_LEN, the
> remaining data is insufficient for further parsing and causes
> hardware TX hang.

Where does RTASE_SHORT_PKT_THRESH come into this?

RTASE_MIN_PAD_LEN is 47, so matches all packets which need padding up
to 60 bytes, plus FCS. There are not many such packets, so why both
this all the complexity and just pad all small packets? Do you have
any performance numbers which show the complexity is worth it?

> Pad these packets so the transport data reaches
> RTASE_MIN_PAD_LEN before transmitting to avoid triggering the
> hardware issue.
> 
> Signed-off-by: Justin Lai <justinlai0215@xxxxxxxxxxx>

Is this a Fix? Please add a Fixes: tag. And base it on net.

https://www.kernel.org/doc/html/latest/process/maintainer-netdev.html

    Andrew

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