On Wed, Nov 26, 2025 at 09:36:42AM +0100, Oleksij Rempel wrote:

My current understanding is that get_pauseparam() is mainly a
configuration API. It seems to be designed symmetric to
set_pauseparam(): it reports the requested policy (autoneg flag and
rx/tx pause), not the resolved MAC state.

In autoneg mode this means the user sees what we intend to advertise
or force, but not necessarily what the MAC actually ended up with
after resolution.

The ethtool userspace tool tries to fill this gap by showing
"RX negotiated" and "TX negotiated" fields, for example:

  Pause parameters for lan1:
    Autonegotiate:  on
    RX:             off
    TX:             off
    RX negotiated:  on
    TX negotiated:  on

As far as I can see, these "negotiated" values are not read from hardware or
kernel. They are guessed in userspace from the local and link partner
advertisements

They are not "guessed". IEEE 802.3 defines how the negotiation resolves
to these, and ethtool implements that, just the same as how we resolve
it in phylib.

Whether the MAC takes any notice of that or not is a MAC driver problem.

, assuming that the kernel follows the same pause resolution
rules as ethtool does. If the kernel or hardware behaves differently, these
values can be wrong.

If it doesn't follow IEEE 802.3 resolution, then it's quite simply
broken. IEEE 802.3 requires certain resolution methods from the
negotiation in order for both link partners to inter-operate.

Don't make this more complex than it needs to be!

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