mii_nway_result(9)

✨ mii_nway_result(9) ✨

okay so this is a page from the Kernel API Manual and honestly? it's a little icon of a function 💅 it takes a bunch of MII abilities and tells you which media type you actually get. let's get into it 🫶

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🌸 NAME 🌸

mii_nway_result —

and yes bestie, the one-liner is genuinely blank upstream 😭 the manpage just... doesn't finish the sentence. not me leaving it exactly as I found it, no cap. the description below is where the tea is ☕

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🎀 SYNOPSIS 🎀

unsigned int mii_nway_result (unsigned int negotiated );

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🦋 ARGUMENTS 🦋

• negotiated — this is the value of MII ANAR and'd with ANLPAR. like, the two auto-negotiation registers smooshed together with a bitwise AND. that's the whole input, periodt 🔥

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💖 DESCRIPTION 💖

so here's the vibe: you hand it a set of MII abilities, it checks each bit, and it returns the currently supported media — in the priority order defined by IEEE 802.3u. iconic. ⭐

it uses LPA_xxx constants, but heads up bestie 🫶 this is not the value of LPA solely — as described above (ANAR AND'd with ANLPAR), remember?

there's exactly one exception to IEEE 802.3u, and it's lowkey important ngl: 100baseT4 is placed between 100T-full and 100T-half. if your phy doesn't support 100T4, that's totally fine, no drama 💅 but if your phy places 100T4 elsewhere in the priority order, then the built-in one won't match your phy and you will need to roll your own function. not me telling you to write your own 😭 but like, fr fr, you gotta.

🚨 tl;dr on the caveat: the ordering is hardcoded to IEEE 802.3u + that one 100T4 tweak. if your hardware disagrees with that ordering, this function isn't it for you.

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🔮 SEE ALSO 🔮

oh you want the whole friend group? say less 👑

• Kernel file ./include/linux/mii.h
• mii_duplex(9)
• ethtool_adv_to_mii_adv_t(9)
• linkmode_adv_to_mii_adv_t(9)
• mii_adv_to_ethtool_adv_t(9)
• ethtool_adv_to_mii_ctrl1000_t(9)
• linkmode_adv_to_mii_ctrl1000_t(9)
• mii_ctrl1000_to_ethtool_adv_t(9)
• mii_lpa_to_ethtool_lpa_t(9)
• mii_stat1000_to_ethtool_lpa_t(9)
• mii_stat1000_mod_linkmode_lpa_t(9)
• ethtool_adv_to_mii_adv_x(9)
• mii_adv_to_ethtool_adv_x(9)
• mii_adv_mod_linkmode_adv_t(9)
• mii_adv_to_linkmode_adv_t(9)
• mii_lpa_to_linkmode_lpa_t(9)
• mii_lpa_mod_linkmode_lpa_t(9)
• linkmode_adv_to_lcl_adv_t(9)
• mii_lpa_mod_linkmode_x(9)
• linkmode_adv_to_mii_adv_x(9)
• mii_advertise_flowctrl(9)
• mii_resolve_flowctrl_fdx(9)
• mii_bmcr_encode_fixed(9)

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and that's the whole page bestie! 🧚 this one's from ./include/linux, dated October 2026 — mwah, go forth and negotiate your link at the highest priority available 💜🌈

#mii_nway_result #iykyk #slay