Chelsio Terminator T4/T5/T6 iWARP RDMA adapters
RDMA (remote direct memory access) support for Chelsio's Terminator T4, T5, and T6 Unified Wire converged Ethernet adapters, which deliver iWARP-style low-latency networking over 10/25/40/100 Gbps Ethernet for storage fabrics, HPC clusters, and database servers from roughly 2010 onward.
recommendation
Worth keeping but worth flagging as a niche corner of the kernel. Chelsio still sells current T6 Unified Wire adapters in 2025 and the driver was still receiving upstream cleanups on the linux-rdma list in 2025, so it has a real (if small) user base and an active vendor. The same vendor page already labels T5 and earlier as legacy, so deployments skew toward specialized storage and HPC shops rather than mainstream servers.
repository signals
sources
- lore.kernel.org
linux-rdma saw a cxgb4 patch on 2026-04-06 ('RDMA/cxgb4: Convert to ib_respond_udata()'), showing current upstream maintenance rather than abandonment.
- chelsio.com
Chelsio's current product page still markets T6 Unified Wire adapters and lists T6 models such as T62100-CR and T6225-CR, indicating related hardware remained on sale after 2025.
- chelsio.com
The same Chelsio page labels 'T5 and Legacy Adapters' separately, implying older generations are legacy even though newer related hardware is still sold.
codex reasoning notes (technical)
Local source read via shell (`sed`/`rg`) identified this as the Chelsio RDMA/iWARP driver; device.c says 'Chelsio T4/T5 RDMA Driver' and code handles CHELSIO_T4/T5/T6. Lore evidence came from `lore_activity` on drivers/infiniband/hw/cxgb4/provider.c, which returned recent linux-rdma activity including the 2026-04-06 cxgb4 patch URL cited above. Removal-signal probes via `lore_regex`, `lore_substr_subject`, and `lei q` did not yield usable evidence (timeouts / sandboxed lei daemon failure), so the recommendation is based on positive maintenance evidence plus current vendor product status. Web evidence came from `web search_query` and `open` on Chelsio's canonical product page, which shows T6 products still offered while classifying T5 as legacy. Conclusion: keep the driver, but annotate it as niche/legacy-leaning hardware support with ongoing maintenance and no clear in-tree replacement.