usb_serial_g..._write_start(9)

✨ usb_serial_g..._write_start(9) ✨

okay so real talk, this is a page straight out of the Kernel API Manual and it's literally the "go go go" button for getting your buffered USB-serial data out the door 💅

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🎀 NAME 🎀

usb_serial_generic_write_start — start writing buffered data

like, the actual kickoff. the moment the buffered stuff finally gets its main character moment 🦋

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🌸 SYNOPSIS 🌸

int usb_serial_generic_write_start (struct usb_serial_port *port , gfp_t
mem_flags );

that's the whole vibe: you hand it a port and some flags, it hands you back an int. no cap 🫶

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💖 ARGUMENTS 💖

• port — a usb-serial port. the lil guy we're writing through 🍓
• mem_flags — the flags to use for memory allocations. yes bestie, allocation flags, not a personality trait, but honestly they kinda are ✨

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🌈 DESCRIPTION 🌈

Serialised using the USB_SERIAL_WRITE_BUSY flag.

that's it, that's the whole description 💀 it keeps everything in line with USB_SERIAL_WRITE_BUSY so two writers don't show up to the same port in the same fit. iconic behavior, honestly 👑

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⭐ RETURN ⭐

• Zero on success or if busy — so zero is a whole spectrum here, it can mean "slay, done" or "chill, someone's already on it" 🙈
• otherwise you get a negative errno value. read that as: something went sideways, check the errno 💀

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🦋 SEE ALSO 🦋

• the Kernel file ./drivers/usb/serial/generic.c — the source of truth, go read it iykyk
• usb_serial_generic_write(9) — the sibling, arguably the more famous one 💅
• usb_serial_handle_dcd_change(9) — the DCD change handler, also part of the friend group 🔥

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ngl, the description is short, but that doesn't mean the flag isn't doing heavy lifting. USB_SERIAL_WRITE_BUSY is the whole safety net — respect it 🧚

alright bestie that's the page 💜 this one lives in ./drivers/usb/serial, stamped October 2026, and it's here for you whenever the kernel API manual drops it in your feed 🎀🫶