Re: [PATCH net-next 2/2] net: dsa: mv88e6xxx: use direct ATU hash on 88E6141/6341

On 4 Jul 2026, at 1:40 am, Andrew Lunn [off-list ref] wrote:

On Fri, Jul 03, 2026 at 04:42:56PM +1000, Luke Howard wrote:

quoted

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.

quoted

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