pcs_inband_caps(9)

💅 pcs_inband_caps — the kernel API manual, bestie edition

okay so this page is pcs_inband_caps(9) and it's literally all about asking your PCS what in-band stuff it can do for a given interface mode. short page, but iconic. let's get into it 🫶

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✨ NAME ✨

pcs_inband_caps — query PCS in-band capabilities for interface mode.

like, "hey bestie, what in-band signalling are you actually about?" that kind of vibe check, but for a PCS. 💅

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🌸 SYNOPSIS 🌸

unsigned int pcs_inband_caps (struct phylink_pcs *pcs , phy_interface_t
interface );

yes the line break is real, no we are not fixing it, it's part of the aesthetic now 🎀

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🦋 ARGUMENTS 🦋

• pcs — a pointer to a struct phylink_pcs. that's the main character here, the PCS you're questioning.
• interface — the interface mode to be queried. this is the "for which mode though?" part, because capabilities are per-interface-mode bestie, not one-size-fits-all ✨

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💖 DESCRIPTION 💖

so here's the tea: this returns zero if it is unknown what in-band signalling is supported by the PHY — for example because the PHY driver doesn't implement the method. not a flex, just a "we genuinely don't know" signal, no cap. 😭

otherwise? it returns a bit mask of the LINK_INBAND_* values from enum link_inband_signalling to describe which inband modes are supported for this interface mode. so like, each bit is a little flag saying "yep, we do this one". very demure, very bitmask. 👑

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/phylink.h — the whole phylink saga lives here, go read it iykyk
• struct phylink_link_state(9)
• struct phylink_config(9)
• struct phylink_mac_ops(9)
• mac_get_caps(9)
• mac_select_pcs(9)
• mac_prepare(9)
• mac_config(9)
• mac_finish(9)
• mac_link_down(9)
• mac_link_up(9)
• mac_disable_tx_lpi(9)
• mac_enable_tx_lpi(9)
• mac_wol_set(9)
• struct phylink_pcs(9)
• struct phylink_pcs_ops(9)
• pcs_validate(9)
• pcs_enable(9)
• pcs_disable(9)
• pcs_get_state(9)
• pcs_config(9)
• pcs_an_restart(9)
• pcs_link_up(9)
• pcs_disable_eee(9)
• pcs_enable_eee(9)
• pcs_pre_init(9)
• phylink_get_link_timer_ns(9)
• phylink_mac_implements_lpi(9)

like i said, whole friend group. go say hi to all of them 🧚💜

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and that's the whole page bestie, no notes. this one's coming at you from ./include/linux and it's dated October 2026, filed under pcs_inband_caps(9). slay, go query some capabilities 💅✨🌈