From: Luke Howard <lukeh@padl.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Vladimir Oltean <olteanv@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Vivien Didelot <vivien.didelot@gmail.com>,
Gregory CLEMENT <gregory.clement@bootlin.com>,
Cedric Jehasse <cedric.jehasse@gmail.com>,
Kieran Tyrrell <kieran@sienda.com>,
Max Holtmann <mh@rme-audio.de>, Max Hunter <max@huntershome.org>,
Christoph Mellauner <christoph.mellauner@joyned.at>,
Simon Gapp <simon.gapp@gapp-audio.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 2/2] net: dsa: mv88e6xxx: use direct ATU hash on 88E6141/6341
Date: Sat, 4 Jul 2026 07:28:12 +1000 [thread overview]
Message-ID: <81F61D3E-D9EB-4646-A401-9C34BAF0903D@padl.com> (raw)
In-Reply-To: <9eea72a5-b30d-4543-ac97-179743d99950@lunn.ch>
> On 4 Jul 2026, at 1:40 am, Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Fri, Jul 03, 2026 at 04:42:56PM +1000, Luke Howard wrote:
>> The default 88E6341/88E6141 ATU hash algorithm appears to result
>> in frequent collisions, evicting permanent registrations (including
>> the broadcast address) out of the ATU.
>
> Is there any documentation about how the 88E6341/88E6141 hashing
> algorithm is different to all the other chips? How is it special?
No documentation, just my experience, which is why I asked in the cover for others to test. I can include test results with the next revision.
>> have a performance impact (the data sheet notes this is for testing
>> only), but it also enables correctness, at least in local testing.
>
> How do you define correctness? Are you using a well defined test?
>
> Why is the devlink parameter not sufficient.
Devlink would indeed be better, but changing hash mode with a non-empty ATU causes it to be corrupt on read back. Perhaps the right solution is to flus the ATU when changing hash mode via devlink.
Luke
next prev parent reply other threads:[~2026-07-03 21:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-03 6:42 [PATCH net-next 0/2] net: dsa: mv88e6xxx: 6141/6341 workarounds Luke Howard
2026-07-03 6:42 ` [PATCH net-next 1/2] net: dsa: mv88e6xxx: write the ATU FID register on 88E6141/88E6341 Luke Howard
2026-07-03 15:31 ` Andrew Lunn
2026-07-03 21:28 ` Luke Howard
2026-07-03 6:42 ` [PATCH net-next 2/2] net: dsa: mv88e6xxx: use direct ATU hash on 88E6141/6341 Luke Howard
2026-07-03 15:40 ` Andrew Lunn
2026-07-03 21:28 ` Luke Howard [this message]
2026-07-03 21:43 ` Andrew Lunn
2026-07-03 21:55 ` Luke Howard
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