The arcmsr(4) driver on FreeBSD 8.4 and FreeBSD 9.0 (or later) has been updated to support ARC-188x/12x3/12x5 series SAS RAID controller. If you use driver older than these versions above, the driver will be not able to recognize the controller and arrays on the controller.
Tags: ARC-12x3, ARC-12x5, ARC-188X, FreeBSD, Q10011502