Re: [PATCH net-next v5 2/5] ethtool: netlink: add ETHTOOL_MSG_MSE_GET and wire up PHY MSE access

From: Oleksij Rempel

Date: Mon Sep 15 2025 - 05:31:33 EST


On Fri, Sep 12, 2025 at 05:00:53PM -0700, Jakub Kicinski wrote:
> On Fri, 12 Sep 2025 12:07:42 +0200 Oleksij Rempel wrote:
> > > > + -
> > > > + name: max-average-mse
> > > > + type: u32
> > > > + -
> > > > + name: max-peak-mse
> > > > + type: u32
> > > > + -
> > > > + name: refresh-rate-ps
> > > > + type: u64
> > > > + -
> > > > + name: num-symbols
> > > > + type: u64
> > >
> > > type: uint for all these?
> >
> > I would prefer to keep u64 for refresh-rate-ps and num-symbols.
> >
> > My reasoning comes from comparing the design decisions of today's industrial
> > hardware to the projected needs of upcoming standards like 800 Gbit/s. This
> > analysis shows that future PHYs will require values that exceed the limits of a
> > u32.
>
> but u64 may or may not also have some alignment expectations, which uint
> explicitly excludes

just to confirm - if we declare an attribute as type: uint in the YAML
spec, the kernel side can still use nla_put_u64() to send a 64-bit
value, correct? My understanding is that uint is a flexible integer
type, so userspace decoders will accept both 4-byte and 8-byte encodings
transparently.

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