ACPI-backed Plug and Play enumeration
Kernel infrastructure that enumerates and assigns resources to motherboard-level devices described in a PC's ACPI firmware tables, such as embedded controllers, real-time clocks, legacy serial and PS/2 ports, and other fixed-function chips identified by PNP IDs. It is the modern ACPI-based replacement for the old PnP BIOS mechanism and is exercised on essentially every ACPI-capable PC.
recommendation
It should stay because this is the bridge that lets the Linux Plug and Play layer discover and assign resources to motherboard devices described in the firmware's ACPI tables (things like embedded controllers, RTCs, PS/2 controllers, and other fixed-function chips identified by PNP IDs such as PNP0C09 or PNP0100). Every modern x86 PC still ships with ACPI, the code is actively maintained with fixes landing as recently as late 2023, and there is no alternative subsystem performing this role.
repository signals
sources
- git.kernel.org
Upstream still touches this directory in current-era kernels, with fixes landing through 2023 rather than the code being abandoned or already removed.
- cateee.net
CONFIG_PNPACPI remains present through current 6.x kernels, and LKDDb ties it to ACPI PNP IDs such as PNP0C09, PNP0C0F, PNP0100, and PNP0000 handled from this directory.
- cateee.net
The parent PnP subsystem is still enabled in current kernels and explicitly supports ACPI-backed enumeration, indicating this code still serves a live kernel feature rather than a retired niche.
- en.wikipedia.org
ACPI is the standard firmware interface used by modern PCs for hardware discovery/configuration and superseded older PnP BIOS mechanisms, so ACPI-backed enumeration remains present on new systems.
- en.wikipedia.org
Legacy Plug and Play was superseded by ACPI, which explains why this driver is old infrastructure but still relevant as the ACPI-side bridge for motherboard/device resource enumeration.
codex reasoning notes (technical)
`core.c`/`rsparser.c` inspected locally via shell `rg`/`sed`: this is real PnP-over-ACPI kernel infrastructure, not docs/helpers. Recent path activity was checked with local `git -c safe.directory=... log`; it shows five substantive touches since 2021, latest 2023-12-06, which argues against deprecation. No lore MCP was available and `lei` was unavailable in the sandbox, so removal-talk evidence was approximated from the lack of obvious recent removal hits in web search plus continuing kernel-path activity. URLs were obtained via web search (`cateee`, Wikipedia) or canonical recall (`git.kernel.org` path log URL). Recommendation is `keep` because this code bridges Linux PnP core to ACPI namespace objects that still exist on shipping ACPI PCs; there is no natural replacement driver for the same role.