Re: [PATCH net-next 2/3] net: stmmac: Allow supporting coarse adjustment mode

Maxime Chevallier
2025-10-23T08:29:58Z

On 22/10/2025 01:02, Jakub Kicinski wrote:
> On Tue, 21 Oct 2025 10:02:01 +0200 Maxime Chevallier wrote:
>> Let me know if you need more clarifications on this
>
> The explanation was excellent, thank you. I wonder why it's designed
> in such an odd way, instead of just having current_time with some
> extra/fractional bits not visible in the timestamp. Sigh.
>
> In any case, I don't feel strongly but it definitely seems to me like
> the crucial distinction here is not the precision of the timestamp but
> whether the user intends to dial the frequency.

Yes indeed. I don't have a clear view on wether this is something unique
to stmmac or if this is common enough to justify using the tsconfig API.

As we discuss this, I would tend to think devlink is the way, as this
all boils down to how this particular HW works. Moreover, if we use a
dedicated hwprov qualifier, where do we make it sit in the current
hierarchy (precise > approx) that's used for the TS source selection ?

Maxime