On CM4 (BCM2711, kernel 6.12.47) we can reliably probe a CSI-2 decoder such as the PixelPlus PR2000K (power, reset, I²C, driver probe, and DT endpoints all confirmed), yet the Unicam pipeline never instantiates because the V4L2 async notifier does not complete and bcm2835_unicam_async_bound() is never called. As a practical example, the same PR2000K (or similar devices, such as ADV728x) binds cleanly on i.MX or Rockchip platforms using an identical DT CSI-2 endpoint graph and produce/dev/video* via standard V4L2 async matching, whereas on Raspberry Pi the device is silently ignored unless it is a firmware-enumerated camera sensor. This strongly suggests a Unicam/firmware policy restriction rather than a DT or driver error. Can you confirm whether Unicam is intentionally limited to firmware-recognized sensors only, and if so, whether there is any supported method (DT, firmware flag, or kernel patch) to enable generic CSI-2 decoders/bridges, or if these devices are simply unsupported by design on Raspberry Pi?
Statistics: Posted by mukam — Sat Jan 03, 2026 10:37 pm