sfp_upstream_stop(9)

💅 sfp_upstream_stop — kernel API manual, section 9

okay bestie, gather round, because this one's a tiny little function with a big job and honestly the glow-up is real. it lives in section 9 of the kernel API manual, and no, it is not a command you type — it's a kernel function, iykyk 🧚

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🌸 NAME 🌸

sfp_upstream_stop — the function that lets the SFP know the network device is down 🫶

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✨ SYNOPSIS ✨

void sfp_upstream_stop(struct sfp_bus *bus);

that's it. that's the whole signature. no return value, no drama, just vibes and a pointer 💅

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🎀 ARGUMENTS 🎀

• bus — a pointer to the struct sfp_bus structure for the sfp module. that's your one (1) job, bestie: hand it the bus 🦋

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🔥 DESCRIPTION 🔥

so here's the tea ☕ — this function informs the SFP socket that the network device is now up, so that the module can be disabled by asserting TX_DISABLE, which disables the laser in optical modules. lowkey iconic behaviour: the module gets told to chill out and the laser goes night-night 😴🔥

(yes, the page literally says "now up" in the description of the stop function — we are simply reporting the facts as written, no cap, we do not editorialise, we just deliver 💀)

and where do you call it from? from the network device driver's struct net_device_ops ndo_stop method, obviously. that's the spot. that's the moment. main character energy only 🌈

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👑 SEE ALSO 👑

go read these next, bestie, they're all in their flop era until you do:

• Kernel file ./drivers/net/phy/sfp-bus.c
• struct sfp_bus(9)
• sfp_select_interface(9)
• sfp_bus_put(9)
• sfp_get_module_info(9)
• sfp_get_module_eeprom(9)
• sfp_get_module_eeprom_by_page(9)
• sfp_upstream_start(9)
• sfp_upstream_set_signal_rate(9)
• sfp_bus_find_fwnode(9)
• sfp_bus_add_upstream(9)
• sfp_bus_del_upstream(9)
• sfp_get_name(9)

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💖 reminder: sfp_upstream_start(9) is literally right there in the list, they're a matching set, do not separate them, they're a package deal 🫶

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and that's the whole page, periodt 🎀 this little legend is brought to you by ./drivers/net/phy, dated October 2026 — slay, see you in the next manpage, mwah 💋✨