Broadcom Sonics Silicon Backplane (SSB) bus
Broadcom's older on-chip interconnect used to glue together the wireless, Ethernet, and SoC blocks inside BCM43xx Wi-Fi cards and BCM47xx home-router chips from the mid-2000s through about 2012. It shows up in plenty of older laptops, mini-PCI Wi-Fi cards, and consumer routers, attached via PCI, PCMCIA, SDIO, or directly on the SoC.
recommendation
Worth keeping but documenting its niche, because the hardware is firmly legacy yet still very much in the field. Broadcom replaced SSB with the newer BCMA bus around 2012 for fresh designs, but huge numbers of older Wi-Fi cards and home routers still depend on the SSB code, and it continues to receive upstream bug fixes (a reference-leak fix landed as recently as 2026). New Broadcom hardware should be using the BCMA driver instead.
repository signals
sources
- lore.kernel.org
`drivers/ssb` still receives upstream bug-fix traffic; a 2026 patch fixes a reference leak in `ssb` code, arguing against removal.
- cateee.net
`CONFIG_SSB` remains in current kernels and the supported PCI IDs are Broadcom 4301/4306/4311/4318/4321/4322-class devices, indicating mostly legacy Broadcom WLAN-era hardware.
- cateee.net
Kernel config text describes SSB support as for 'old Broadcom BCM47XX boards', which is direct evidence that the SoC/router side is legacy rather than current-production hardware.
- cateee.net
Kernel config text describes BCMA support as for 'new Broadcom BCM47XX boards', making BCMA the natural successor bus driver for newer Broadcom deployments.
codex reasoning notes (technical)
Local shell `rg` on `drivers/ssb`/`Kconfig` showed this is a real Broadcom SSB bus-driver subtree spanning PCI/PCMCIA/SDIO/SoC hosts. `lore_file_timeline` on `drivers/ssb/main.c` showed recent 2025-2026 fixes and no obvious removal trend in recent activity, so removal/deprecation would be premature. Web search opened LKDDb pages for `SSB`, `BCM47XX_SSB`, and `BCM47XX_BCMA`; those pages label SSB boards as old and BCMA boards as new, supporting 'legacy but still deployed'. `last_widely_available_year` is an inference from the SSB-to-BCMA transition window, not a directly dated vendor-EOL citation.