IDT 89HPES Gen2 PCIe Switch Non-Transparent Bridges
Support for the non-transparent bridging (NTB) function on IDT's 89HPESxxNTxxG2 family of PCIe Gen2 switches, originally sold by IDT and later by Renesas after its 2019 acquisition. These chips let two independent host systems share a PCIe fabric across a backplane, and were used mainly in mid-2010s embedded and storage-server designs that needed dual-host failover or inter-host messaging.
recommendation
Worth keeping but flagging as legacy hardware. Renesas now lists the specific supported parts (such as 89H24NT6AG2 and 89H32NT24BG2) as obsolete and no longer for sale, so deployments are limited to existing embedded and server backplanes. However, the code is not abandoned upstream — it was still receiving NTB-core API updates as recently as December 2025 — so there is no case for removal yet, just an annotation that the silicon is end-of-life.
repository signals
sources
- lore.kernel.org
The driver still receives upstream API-adjustment work as part of active NTB core changes, so it is not abandoned in-tree.
- renesas.com
Renesas marks 89H24NT6AG2 as Obsolete; this is one of the exact 89HPES24NT6AG2-family devices supported by the driver.
- renesas.com
Another exact supported device variant, 89HPES32NT24BG2, is also marked Obsolete, indicating the supported family is no longer in new-sale status.
- renesas.com
The datasheet identifies the part as an IDT PCIe Gen2 system interconnect switch with multiple Nontransparent Bridging functions, matching the Linux driver's scope.
codex reasoning notes (technical)
Local shell (`rg`, `sed`) on the kernel tree identified supported IDs 89HPES24NT6AG2/32NT8AG2/32NT8BG2/12NT12G2/16NT16G2/24NT24G2/32NT24AG2/32NT24BG2 and Kconfig describes this as an IDT PCIe-switch NTB driver. `lore_file_timeline` on `drivers/ntb/hw/idt/ntb_hw_idt.c` showed recent 2025 touches and no evident removal traffic in the returned history, so removal/deprecation is not justified by upstream activity. Web search found official Renesas product pages showing exact supported parts marked Obsolete, plus the datasheet describing NTB-capable PCIe Gen2 switch silicon. Conclusion: silicon is obsolete and likely limited to legacy embedded/server backplanes, but there is still some upstream maintenance; annotate as legacy/obsolete hardware rather than deprecate now.