This is the easiest way I found to do this on i2 (and maybe i4/i6) bl860c i2 blades:
drivers
# in first column, find the driver that corresponds to Smart Array SAS Driver
# in my case it was A3
devices
# in first column, find the device, Smart Array P420i Controller
# in my case it was A1
drvcfg -s a3 a1
sometimes you get a "drvcfg: Driver image handle [A3] does not support Driver Configuration Protocol"
that is most likely the version of the EFI driver, v3.54 supports this, but at least v3.50 does not
