efx_siena_mcdi_rpc_async(9)

💅 efx_siena_mcdi_rpc_async — Kernel API Manual, bestie edition ✨

Okay so welcome to the efx_siena_mcdi_rpc_async page, aka the Kernel API Manual flex you didn't know you needed. No cap, this one's lowkey iconic — it's the async sibling of the MCDI RPC crew and it's giving "fire and forget, but in a driver-safe way" 🦋

---

✨ NAME ✨

efx_siena_mcdi_rpc_async — schedule an MCDI command to run asynchronously, fr fr 🎀

---

🌸 SYNOPSIS 🌸

int efx_siena_mcdi_rpc_async (struct efx_nic *efx , unsigned int cmd ,
       const efx_dword_t *inbuf , size_t inlen , size_t outlen ,
       efx_mcdi_async_completer *complete , unsigned long cookie );

Literally just look at it. Main character signature energy 👑

---

🫶 ARGUMENTS 🫶

• efx — the NIC you're issuing the command through. That's the vibe portal, basically 💫
• cmd — the command type number. Just a number. Numbers are valid. Slay 🔢
• inbuf — the command parameters go in here 🍓
• inlen — how long those command parameters are, in bytes. Bytes, bestie, not vibes 💀
• outlen — how much space to allocate for the response buffer, also in bytes ✨
• complete — the function that gets called on completion or cancellation. So it's the callback. The "text me when you're done" function 📲
• cookie — an arbitrary value that gets passed to complete. It's a little treat you hand over so your callback knows what's up 🍪

---

💖 DESCRIPTION 💖

Real talk: this function does not sleep, which means it may literally be called in atomic context. Atomic context besties, we love a non-blocking icon 😭

Heads up though — it will fail if event queues are disabled, or if MCDI event completions have been disabled because of an error. Not a vibe, but that's the deal 🙈

If it succeeds? The complete function will be called exactly once, in atomic context, when one of these three things happens — and only these three, iykyk:

1. The completion event is received — that's in NAPI context ⭐
2. Event queues are disabled — that's in the process that disables them 🧚
3. The request times-out — that's in timer context 🔥

Exactly once is the key part. Not zero, not twice. Once. Periodt 💅

---

🌈 SEE ALSO 🌈

• Kernel file ./drivers/net/ethernet/sfc/siena/mcdi.c — go read the source, it's right there 👀
• efx_siena_mcdi_rpc(9) — the sync one, for when you actually feel like waiting around 🦋

---

And that's the whole page, bestie! 💜 This little love letter comes straight out of ./drivers/net/ethernet/sfc/siena, dated October 2026, and it's filed under efx_siena_mcdi_rpc_async(9) in the Kernel API Manual. Go forth and async responsibly 🎀✨