PNP(4)

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

💖 PNP(4) 💖

okay bestie, so this is the page for pnp — it lives in the i386 Kernel Interfaces Manual and it's all about "Plug and Play" (PnP) ISA devices. yes, the literal quoted name, quotes and all, it's giving 1994 and we love her for it ✨

🌸 NAME 🌸

pnp — support for “Plug and Play” (PnP) ISA devices 🫶

✨ DESCRIPTION ✨

okay so the pnp driver goes around the system and enumerates ISA devices that support the “Plug and Play ISA Specification”. like, it finds them all, one by one, no cap. 👑

then for each device it does the whole matchmaking thing: it assigns ISA bus resources to the device — and those resources are:

  • interrupt line
  • DMA channel
  • I/O ports
  • memory region

and after it hands those over, it activates the device. iconic behaviour tbh. 💅

😭 but here's the sad part: if it cannot assign the necessary resources to a PnP ISA device without causing conflict with other devices in the system, the device will not be activated and will be unavailable to programs. it just... doesn't show up. not me crying over an unconfigured ISA card fr fr.

🦋 SEE ALSO 🦋

📜 STANDARDS 📜

our girl follows the receipts, and the receipts are:

  • Intel and Microsoft, Plug and Play ISA Specification, Version 1.0a, May 5, 1994.
  • Clarifications to the Plug and Play ISA Specification, Version 1.0a, December 10, 1994.

🌈 HISTORY 🌈

The pnp driver first appeared in FreeBSD 2.2.5. 💀 she's old. and she's been substantially updated in subsequent versions — glow-up after glow-up, we stan an evolving queen. ✨

👑 AUTHORS 👑

PnP support was originally written for FreeBSD 2.2.5 by Luigi Rizzo, based on initial work done by Sujal Patel. legends only. 🫶

💀 CAVEATS 💀

bestie. sit down. 🍓

  • It is not possible to disable individual PnP ISA devices. The pnp driver will find all devices conforming the PnP ISA specification and try to activate them all. every single one. no picking and choosing, no skipping, no "not that one". it's all or nothing and she chose all. 🙈
  • There is no way to explicitly assign a particular resource to the PnP ISA device. The resource assignment is fully automatic and there is no provision for manual override. zero. none. the machine decides, you just vibe. 😭

and that's the whole page, mwah 💋 — this beauty comes to you from Debian, dated September 20, 2001, so go forth and let the ISA bus cook 🔥

📦 where this page comes from