Re: [PATCH net-next v4 0/5] ionic: Expose more port stats to ethtool

[Jakub Kicinski <kuba@kernel.org>]

On Sat, 13 Jun 2026 18:34:23 -0700 Eric Joyner wrote:
> I could add the overflow and reset handling (I was working on it for a v5), but
> to me, it didn't seem like it was worth the effort to modify the stat from
> firmware instead of continuing to use the existing driver-calculated stat. It
> wasn't really a "can I do this" question but more "is it worth doing this?"
> 
> To start, it didn't seem like there was a specific standard that the API
> expected; it looked like "copy straight from the adapter if you can, or just
> calculate something if you can't". It's hard to tell what the actual
> expectations for the interface outside of the struct comment since there aren't
> many drivers using it. The Mellanox and Broadcom driver stat handlers just read
> the link down count straight from hardware (though I don't know if those stats
> get reset on driver load or reboot and we're the outlier in the way our firmware
> behaves). The Intel drivers are similar to what we do now in the ionic driver,
> and they just count the link down events that the driver detects, but I know
> that they don't expose a link down count from the hardware.  What we do now
> seems good enough for that purpose? It's bigger than 16 bits and gets reset on
> driver load, so why add more code to handle something that this seems to do well
> enough?
> 
> But, I also still want the raw firmware stat because the firmware has a
> different lifetime than the driver, and so it will count link down events while
> the driver isn't loaded or in a state to receive link events. But since maybe
> that's only useful for debugging, it belongs in debugfs instead? I just thought
> drivers could more or less put what they want in `ethtool -S` output, so that
> seemed like an okay place to put it.

I sent a patch to delete this incorrect stat ASAP. Feel free to add it
to ethtool -S under a name that clearly indicates that it's _not_ the
phy down count in the next cycle.