Re: [PATCH net 5/6] net: stmmac: selftests: Account for the UC filter list for filtering tests

[Maxime Chevallier]

Hi,

On 8/26/26 20:25, Andrew Lunn wrote:
> On Wed, Aug 26, 2026 at 04:04:57PM +0200, Maxime Chevallier wrote:
>> On dwmac, one of the Unicast filter entries is used to store the local
>> HW addr. This means that we have to use promisc mode for any kind of
>> unicast filtering if we only have one slot in our unicast filter.
>>
>> The number of slots available depends on how the IP is integrated, and
>> we can't autodiscover how many of these slots we have available, so
>> the DT property snps,perfect-filter-entries can be used to specify how
>> many are available.
>>
>> Most IP variants default to 1 if this isn't specified, which is the case
>> for the amlogic variants (in this case, S905X3).
> 
> Do you have this hardware? Did you try increasing the DT property to
> find out how many slots it actually has?

I do have the HW, but I haven't tried figuring the actual number of slots,
there's the same issues on lots of devices actually.

The platform I'm using for that is the Banana Pi M5, not too expensive
(that is, if we compare that with other SBCs)

> Maybe a nice little project for a newbie which has some stmmac
> hardware. Write some code which adds MAC addresses and reads them back
> again. Determine at runtime how many slots there actually are.

Exactly, that thought also crossed my mind, that would be fairly easy to
implement and with a net benefit :)

> 
>> Fixes: 091810dbded9 ("net: stmmac: Introduce selftests support")
>> Signed-off-by: Maxime Chevallier <maxime.chevallier@xxxxxxxxxxx>
> 
> Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
> 
>     Andrew

Thanks for reviewing all of this,

Maxime