Arm64 ACPI platform firmware support (IORT, GTDT, AGDI, APMT)
Plumbing that lets Linux consume ACPI firmware tables on 64-bit Arm server platforms, covering interrupt and IOMMU topology (IORT), generic timers (GTDT), watchdog (AGDI), performance monitoring (APMT), and CPU idle. It is what lets Arm server CPUs such as Ampere Altra/AmpereOne and NVIDIA Grace boot under the standard Arm ServerReady firmware contract.
recommendation
It should stay because this is the firmware glue Linux uses to boot on Arm ServerReady / SBBR-compliant 64-bit Arm servers, the same contract used by current shipping silicon like Ampere's AmpereOne and NVIDIA's Grace CPU. The code is under active development, with new IORT and AGDI work landing in 2025-2026 and no removal discussion in sight.
repository signals
sources
- lore.kernel.org
Recent 2026 upstream work adds new IORT functionality, showing the directory is under active development rather than retirement.
- lore.kernel.org
AGDI support was still being extended in 2026, indicating ongoing enablement for current arm64 ACPI platforms.
- developer.arm.com
Arm ServerReady material states SBBR covers ACPI for Arm server systems, matching this directory's role as current firmware-interface support.
- amperecomputing.com
AmpereOne is a current Arm server-class processor family, showing new Arm server hardware remains in market.
- nvidia.com
NVIDIA Grace CPU is a current Arm server platform, further showing ongoing new deployments of Arm server hardware.
codex reasoning notes (technical)
Local source inspection via shell showed this directory is real arm64 ACPI platform support (IORT, GTDT, AGDI, APMT, MPAM, AMBA, cpuidle), not a dead compatibility shim. Lore evidence was obtained with `lore_regex` and `lore_file_timeline`: recent 2025-2026 patches add features and fixes, and no removal signal was found; a `lei` removal query was attempted but failed due local socket permission restrictions. Deployment evidence came from web search hits on Arm ServerReady/SBBR and current AmpereOne/NVIDIA Grace product pages. Because ACPI remains the standard firmware contract for a meaningful slice of new Arm servers and the code is actively maintained, the correct recommendation is keep.