libnvme_write_reg64(9)

📦 version 3.2, in arch rolling

🌸 libnvme_write_reg64 — the libnvme API manual, bestie edition 🌸

okay so this page lives in the libnvme API manual and it's all about libnvme_write_reg64(9), which — say it with me — writes a 64-bit controller register of a PCIe controller. iconic behavior honestly ✨

💖 NAME 💖

libnvme_write_reg64 — write a 64-bit controller register of a PCIe controller 🎀

🦋 SYNOPSIS 🦋

int libnvme_write_reg64 (struct libnvme_transport_handle *hdl , __u32
offset , __u64 value , bool mmio32 );

like, that's the whole vibe. four args, one int back. slay 💅

✨ ARGUMENTS ✨

  • hdl — the transport handle 🫶 your little passport to the transport, basically.
  • offset — offset of the register, in bytes. yes, bytes. keep up bestie 💖
  • value — the value you're writing. the actual payload, the main character 👑
  • mmio32 — write the register as two 32-bit values, low half first. some devices literally do not support 64-bit MMIO, so this is your fallback queen 🧚 lowkey important.

🌈 DESCRIPTION 🌈

so here's the tea: offset must be a multiple of 8. not optional, not a suggestion, fr fr — multiple of 8 or nothing 💀

and this one should only be sent to controller handles, not to namespaces. like, read the room. controller handles only. no cap 🚫

⭐ RETURN ⭐

0 on success, or a negative error code otherwise — that's the whole dealio 💜

and specifically: -ENOTSUP means the transport has no memory-mapped registers. so if you see that, it's not you, it's the transport 😭🙈

and that's the page!! mwah 💋 — this lil masterpiece comes from the libnvme API manual, source/version libnvme_write_reg64, dated October 2026. go write some registers bestie, you got this 🎀🔥💅

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