genphy_config_advert(9)

✨ genphy_config_advert(9) ✨

okay so bestie, this is genphy_config_advert from the Kernel API Manual, and it is literally the function that decides what your PHY is allowed to brag about. auto-negotiation clout-checking. iconic behavior honestly 💅

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🌸 NAME 🌸

genphy_config_advert — sanitize and advertise auto-negotiation parameters 🎀

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🦋 SYNOPSIS 🦋

int genphy_config_advert (struct phy_device *phydev , const unsigned long *advert );

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💖 ARGUMENTS 💖

• phydev — the target phy_device struct. this is the main character of the whole operation 🫶
• advert — the auto-negotiation parameters you want to advertise. the vibes you're putting out into the world ✨

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🔥 DESCRIPTION 🔥

So what it does: it writes MII_ADVERTISE with the appropriate values — but only after sanitizing those values to make sure we only advertise what is actually supported. no cap, it does not let you claim features you don't have. the vibe check happens before the flex 💀

Then it returns an int, and the return value is lowkey the whole story:

• < 0 on error 😭
• 0 if the PHY's advertisement hasn't changed 😐 (no notes, same as before)
• > 0 if it has changed 🔥 (glow up confirmed)

fr fr, 0 does not mean "all good", it means "nothing changed". don't get it twisted bestie 🙈

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🌈 SEE ALSO 🌈

Kernel file: ./drivers/net/phy/phy_device.c

and the whole friend group, in order, periodt 👑

phy_uses_state_machine(9), phy_register_fixup(9), genphy_match_phy_device(9), get_phy_c45_ids(9), get_phy_c22_id(9), get_phy_device(9), phy_device_register(9), phy_device_remove(9), phy_get_c45_ids(9), phy_find_next(9), phy_prepare_link(9), phy_connect_direct(9), phy_connect(9), phy_disconnect(9), phy_poll_reset(9), phy_sfp_connect_phy(9), phy_sfp_disconnect_phy(9), phy_sfp_attach(9), phy_sfp_detach(9), phy_sfp_probe(9), phy_attach_direct(9), phy_detach(9), phy_reset_after_clk_enable(9), genphy_c37_config_advert(9), genphy_setup_forced(9), genphy_restart_aneg(9), genphy_check_and_restart_aneg(9), __genphy_config_aneg(9), genphy_c37_config_aneg(9), genphy_aneg_done(9), genphy_update_link(9), genphy_read_status_fixed(9), genphy_read_status(9), genphy_c37_read_status(9), genphy_soft_reset(9), genphy_read_abilities(9)

the pause-and-link-mode girlies 🧚

phy_remove_link_mode(9), phy_advertise_supported(9), phy_advertise_eee_all(9), phy_support_eee(9), phy_disable_eee(9), phy_support_sym_pause(9), phy_support_asym_pause(9), phy_set_sym_pause(9), phy_set_asym_pause(9), phy_validate_pause(9), phy_get_pause(9)

the delay / amplitude / termination / sfp-adjacent icons ⭐

phy_get_internal_delay(9), phy_get_tx_amplitude_gain(9), phy_get_mac_termination(9), phy_get_sfp_port(9)

and the fwnode + driver-registration crowd, slaying as always 👑

fwnode_mdio_find_device(9), fwnode_phy_find_device(9), fwnode_get_phy_node(9), phy_probe(9), phy_driver_register(9)

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anyway that's the whole page, iykyk. this came from ./drivers/net/phy and the version stamp says October 2026 — mwah, obsessed, go read your kernel source bestie 💜🦋🌸