ISA Plug and Play bus support
Bus-level support for ISA Plug and Play, the late-1990s auto-configuration scheme that let ISA cards (sound cards, modems, NICs, industrial I/O boards) advertise their resources instead of needing manual jumper settings. It was the bridge between hand-configured ISA hardware and PCI, and today mainly matters for retro PCs and surviving industrial systems with ISA backplanes.
recommendation
Worth keeping but documenting its niche because ISA PnP is the auto-configuration protocol for 1990s ISA expansion cards and was superseded by PCI before the turn of the century. It still receives small upstream fixes in 2025 and is a build dependency for several in-tree legacy drivers (notably some ISA sound cards and a staging GPIB driver that recently needed an export restored), so removing it would break those niche users. A note flagging it as obsolete ISA-era infrastructure retained for legacy industrial and hobbyist systems would help set expectations.
repository signals
sources
- spinics.net
August 25, 2025 review thread shows isapnp still receives upstream maintenance and patches are being applied.
- cateee.net
CONFIG_ISAPNP remains present in current kernels through 6.19 and HEAD, so the subsystem is still shipped upstream.
- kernelconfig.io
CONFIG_ISAPNP is still depended on by several legacy drivers, including ISA sound drivers, showing remaining in-tree consumers.
- en.wikipedia.org
ISA Plug and Play was superseded by PCI during the mid-1990s, indicating the hardware class is long obsolete for mainstream new systems.
- en.wikipedia.org
ISA disappeared from consumer desktops many years ago and survives mainly in specialized industrial legacy niches.
- git.zx2c4.com
A 2025 commit re-exported isapnp_read_byte because a staging GPIB driver needed it, showing live but niche dependency rather than abandonment.
codex reasoning notes (technical)
Local shell inspection shows this directory is real ISA PnP bus support, not a helper-only folder; Kconfig still exposes CONFIG_ISAPNP and headers export APIs used by other legacy drivers. Local git log shows 2020-2025 traffic is mostly small fixes/treewide churn, but there are real 2025 touches including symbol export restoration for staging/gpib and an accepted cleanup patch; web search on spinics confirmed current upstream attention and no obvious removal thread. Web search on LKDDb/kernelconfig showed the option is still upstream and still has in-tree dependents, so outright removal would regress niche legacy users. Web search on Wikipedia indicates ISA PnP was superseded in the mid-1990s and ISA survives mainly in industrial legacy deployments, so new 2025 deployments are not meaningful while existing deployments are low but nonzero. Recommendation is keep-annotate: retain for legacy support, but mark/document it as obsolete ISA-era functionality with niche remaining users. URLs obtained via web search; maintenance evidence also cross-checked from local shell git log.