[PATCH net-next 2/2] net: stmmac: dwmac4: Use the full perfect filter ability for UC filter

Maxime Chevallier maxime.chevallier at bootlin.com
Tue Sep 1 05:27:40 PDT 2026



On 9/1/26 14:21, Andrew Lunn wrote:
> On Tue, Sep 01, 2026 at 08:37:20AM +0200, Maxime Chevallier wrote:
>> Hi,
>>
>> On 9/1/26 02:12, Andrew Lunn wrote:
>>> On Mon, Aug 31, 2026 at 09:01:20AM +0200, Maxime Chevallier wrote:
>>>> Contrary to dwmac1000 that gets its number of perfect filter entries
>>>> through the 'snps,perfect-filter-entries' property, dwmac4 allows
>>>> reading the filter size from the HW features registers.
>>>
>>> Does dwmac4 take any notice of "snps,perfect-filter-entries"? Should
>>> it be marked deprecated?
>>
>> It's only used on :
>>
>>   "st,spear600-gmac"
>>   "snps,dwmac-3.50a"
>>   "snps,dwmac-3.70a"
>>   "snps,dwmac-3.72a"
>>   "snps,dwmac"
>>
>> So, dwmac1000.
>>
>> I'd say, we can definitely deprecate on IPs that don't match these.
>>
>> Interestingly, there are _some_ dwmac4 devicetrees out there that use
>> this property. It achieves nothing, and even worse, doesn't match what
>> the HW reports :
>>
>> In arch/riscv/boot/dts/starfive/jh7110.dtsi for example :
>>
>> gmac1: ethernet at 16040000 {                                            
>> 	compatible = "starfive,jh7110-dwmac", "snps,dwmac-5.20";
>> 	[...]
>> 	snps,perfect-filter-entries = <256>;
>> }
> 
> So another thing for the TODO list, extend the YAML description to
> make properties conditional on the IP core version, so the validator
> tools will pick this up.

Looks like it yes. I'm starting to wonder if we should  maintain this kind
 of TODO list in the kdoc. I know these types of lists have a nasty
tendancy of falling into disrepair, but this could help.

Maxime

> 
> 	Andrew




More information about the linux-arm-kernel mailing list