Re: [PATCH] net: phy: honor eee_disabled_modes in phy_support_eee()

[Andrew Lunn <andrew@lunn.ch>]

On Sat, May 16, 2026 at 06:51:02AM +0200, Nicolai Buchwitz wrote:
> phy_support_eee() copies supported_eee into advertising_eee
> unconditionally, overwriting any filtering applied during phy_probe()
> based on DT eee-broken-* properties or driver-populated
> eee_disabled_modes. MAC drivers that call phy_support_eee() after
> probe (e.g. bcmgenet, fec, lan743x, lan78xx, r8169) then cause the PHY
> to advertise EEE for modes the user marked as broken.
> 
> The symptom is that ethtool --show-eee on the local interface reports
> "not supported" (supported & ~eee_disabled_modes is empty) while the
> link partner sees EEE negotiated and active.
> 
> phy_probe() already filters advertising_eee via eee_disabled_modes
> after calling of_set_phy_eee_broken(). Apply the same mask in
> phy_support_eee() so the filtering survives the copy.

I don't think this not the full fix.

of_set_phy_eee_broken() sets phydev->eee_disabled_modes.

genphy_c45_ethtool_get_eee() masks supported_eee with this when
reporting to user space what is supported.

genphy_c45_ethtool_set_eee() will also mask what user space passes in,
if it is not empty. However, if nothing is passed in,
phy_advertise_eee_all() is used, and that does not make use of
phydev->eee_disabled_modes, which i think it should.

So while your fix seems correct, i don't think on its own, it is
sufficient. Whenever phydev->supported_eee is used, we need to review
the code and see if it should be masked by phydev->eee_disabled_modes.

    Andrew

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pw-bot: cr