KBDMUX(4)

📦 version 12.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

💖 KBDMUX(4) — bestie, it's the keyboard multiplexer 💖

okay so real talk, this is a page from the Kernel Interfaces Manual (section 4, the driver girlies 🫶). sit down, grab a snack, we're talking about kbdmux.

✨ NAME ✨

kbdmux — the keyboard multiplexer, aka the friend group of keyboards 👑

✨ SYNOPSIS ✨

the whole vibe, in one line:

device kbdmux

and if you need to be a little ✨mysterious✨ about it, pop this into /boot/device.hints:

hint.kbdmux.0.disabled="1"

✨ DESCRIPTION ✨

so the kbdmux keyboard driver is out here providing support for basic keyboard multiplexing. that's it, that's the job. 💅

and the way it's built? it's built around the idea of a “super keyboard”. yes bestie, a super keyboard. no cap. 🔥

here's how it works: the kbdmux driver acts as a master keyboard, and it consumes input from all the slave keyboards attached to it. it's giving main character energy, honestly — all the other keyboards are just feeding it content. 👑

and the way you attach or detach those slave keyboards? you use the kbdcontrol(1) utility. that's the tool. that's how you do it. ✨

✨ SEE ALSO ✨

the whole little family, go say hi:

✨ HISTORY ✨

the kbdmux module was implemented in FreeBSD 6.0. a legend was born. 🌸

✨ AUTHORS ✨

Maksim Yevmenkin <m_evmenkin@yahoo.com> — we love her, we thank her, periodt. 🎀

✨ CAVEATS ✨

okay this part matters, so listen up bestie 🫶

the kbdmux keyboard driver switches all slave keyboards into K_RAW mode. all of them. every single one. 🙈

and because of that, all slave keyboards attached to the kbdmux keyboard share the same state. like, one shared braincell. literally. 😭

so the kbdmux keyboard is logically equivalent to one keyboard with lots of duplicated keys. that's the whole situation. that's what you're getting. and honestly? iconic. 🦋

this page is from Debian, and it's dated July 12, 2005 — and that's the whole KBDMUX(4) moment, mwah, bye bestie 💖✨

📦 where this page comes from