Realtek RTS52xx/RTL8411 and Alcor AU66xx PCIe/USB card reader controllers
Shared low-level support for the SD/MMC/MemoryStick card-reader chips that Realtek and Alcor Micro embed in laptops and handheld PCs. The Realtek RTS52xx and RTL8411 family and Alcor's AU6601/AU6621/AU6625 controllers sit on PCIe (and in some cases USB) and provide the slot you push an SD card into; they remain common in mainstream notebooks and recent handheld gaming PCs like the AYANEO line.
recommendation
Worth keeping, with a note that this is niche removable-media hardware rather than mass storage. The chips still ship in current laptops (e.g. Lenovo ThinkPad P1) and handhelds, and upstream work was active well into 2025-2026, including new SD Express mode support for the Realtek RTS5261 and ongoing fixes on the Alcor side. There is no removal pressure; the code is maintained and continues to land features.
repository signals
sources
- lore.kernel.org
Upstream work was still adding functional fixes in 2026 for the rtsx/MMC stack ('reset power state on suspend').
- lore.kernel.org
The driver family was still receiving stable-backported feature/support work in 2026 ('Add SD Express mode support for RTS5261').
- lore.kernel.org
The Alcor side of the directory also saw non-treewide maintenance in 2025 ('Use non-hybrid PCI devres API').
- linux-hardware.org
RTS5261 appears in modern notebook/handheld probes, including Lenovo ThinkPad P1 and AYANEO systems, indicating ongoing real-world deployment.
- linux-hardware.org
Alcor AU6621 still shows deployed systems in the field, though mostly older notebook platforms.
- cateee.net
LKDDb shows current kernel support for a broad Realtek PCIe card-reader family, including newer RTS5261/RTS5264 IDs.
- cateee.net
LKDDb shows current kernel support for Alcor AU6601/AU6621/AU6625 PCIe card-reader controllers.
codex reasoning notes (technical)
Local shell inspection of Kconfig/Makefile showed this directory is a real driver set for Realtek/Alcor PCIe and USB card-reader controllers, not helper-only code. Lore evidence came from MCP `lore_file_timeline` on `drivers/misc/cardreader/rtsx_pcr.c` and `drivers/misc/cardreader/alcor_pci.c`; those timelines surfaced 2025-2026 fixes/backports and no removal trend in the fast path. URLs cited from lore were obtained directly from those MCP results. Deployment evidence came from web-opened linux-hardware and LKDDb pages found via web search. Net: niche hardware, but still present in newer laptops/handhelds and still seeing upstream maintenance, so deprecation/removal is not justified; annotate at most for niche/legacy media focus.