AMD EPYC Non-Transparent Bridge (NTB) PCIe interconnect
Support for the Non-Transparent Bridge feature built into AMD EPYC and EPYC Embedded processors, starting with first-generation Zeppelin parts and continuing through Starship/Matisse and the current 9005 series. NTB lets two servers be linked directly over PCIe so they can share memory and messages, a trick used mostly in high-availability storage appliances and embedded multi-host systems.
recommendation
Worth keeping but documenting its niche: AMD is still actively maintaining the code, with patches landing as recently as 2025 from AMD itself and follow-up fixes from Oracle in 2026, and the hardware feature is advertised on current EPYC Embedded 9005 and 7002 product pages for HA storage and multi-host networking. Real-world deployment is narrow — it mainly shows up in specialized embedded and high-availability gear rather than general-purpose servers — so an annotation clarifying the audience would help, but removal would be premature while the silicon is still being sold new.
repository signals
sources
- lore.kernel.org
Upstream activity is current: AMD posted a 2025 ntb_hw_amd patch to support latest-generation secondary-topology handling.
- lore.kernel.org
The driver still receives routine upstream fixes in 2026, indicating it is maintained rather than abandoned.
- cateee.net
LKDDb shows CONFIG_NTB_AMD is still present in current kernels and maps the driver to Zeppelin and Starship/Matisse NTB PCI IDs plus newer AMD IDs.
- amd.com
AMD's 2025 EPYC Embedded 9005 product brief lists NTB as a current embedded feature and describes HA multi-host networking/storage use cases.
- amd.com
AMD's EPYC Embedded 7002 product page advertises NTB as an embedded-market feature with extended availability, supporting ongoing deployed use in embedded/server niches.
codex reasoning notes (technical)
Real PCI driver confirmed by local shell inspection of drivers/ntb/hw/amd/ntb_hw_amd.c, including pci_driver registration and AMD/HYGON PCI IDs. Lore evidence came from mcp__lore_http__.lore_file_timeline on the .c file; it showed active 2025-2026 patch traffic and no visible removal thread in recent subjects. Deployment evidence came from web search plus open/find on AMD product pages and LKDDb. Recommendation is keep-annotate because the hardware is still sold for niche HA embedded/server platforms, but deployment is specialized rather than broad mainstream.