write_fifo(9)

📦 version 7.3.1, in nixpkgs unstable

💅 write_fifo(9) — the group chat version ✨

okay so bestie, you're looking at write_fifo, straight out of the write_fifo(9) Kernel API Manual section. buckle up 🎀

🌸 NAME 🌸

write_fifo — transfer packets from a usb request into an IN endpoint 💌

✨ SYNOPSIS ✨

int write_fifo (struct pxa_ep *ep , struct pxa27x_request *req );

🫶 ARGUMENTS 🫶

  • ep — the pxa physical endpoint, like, the actual hardware door you're pushing stuff through 🚪
  • req — the pxa usb request, aka the lil parcel of data that wants to go out 📦

👑 DESCRIPTION 👑

So what this icon does: it writes to an IN endpoint fifo, and it pushes as many packets as possible while it's at it 🔥. Not one, not two — as many as it can, no cap.

irqs will use this to write the rest later, so don't stress about the leftovers, the interrupts got you 💖.

The caller guarantees at least one packet buffer is ready (or a zlp) before calling this — that's the deal, that's the contract, don't skip it bestie 🙈.

It doesn't complete the request. That's the caller's job, not this function's. this function hands off and dips 💅.

returns 1 if the request fully transferred, 0 if it's a partial transfer — that's the vibe check right there ⭐

🦋 SEE ALSO 🦋

Kernel file ./drivers/usb/gadget/udc/pxa27x_udc.c is where the magic lives, and these are all the besties it runs with 👯:

and that's the whole page, bestie, you ate that 🍓 mwah 💜

this one comes to you from ./drivers/usb/gadget/udc, dated October 2026, filed under write_fifo(9) — iconic, no notes 👑✨

📦 where this page comes from