This interface uses a device node used by various MPT Fusion
drivers. It is called '/dev/mptctl' or '/dev/mpt2ctl' and it
is a char device (major: 10, minor: 220 or 221).
Currently a special module needs to loaded called 'mptctl'.
This can be loaded with 'modprobe mptctl'. If there are multiple
MPT Fusion HBAs on one computer then the following construction:
'/dev/mptctl,<n>' can be used for the <smp_device> argument.
LSI Logic call the <n> a "ioc" number. If not given it defaults
to 0 .

There is a pass through ioctl defined for the /dev/mptctl
device which this library uses. Since '/dev/mptctl,<n>' only
describes a SMP host (initiator), the SAS address of the target
SMP device must also be given. This can be done on the command
line (with the '--sa=<sas_addr>' option) or with the environment
variable SMP_UTILS_SAS_ADDR set to the SAS address of the SMP
target device.

To save typing, the SMP host (i.e. '/dev/mptctl,<n>') can be
placed in the SMP_UTILS_DEVICE environment variable

Douglas Gilbert
29th December 2008
