First check if the PCI card is visble to the system

lspci |grep Mellanox
06:00.0 Network controller: Mellanox Technologies MT27500 Family [ConnectX-3]
09:00.0 InfiniBand: Mellanox Technologies MT26428 [ConnectX VPI PCIe 2.0 5GT/s – IB QDR / 10GigE] (rev b0)

Then install the Xsigo burn utiltiy

rpm ivh xsigo-hca-firmware-4.0.3.r177.XGBOOT-1.i386.rpm

Then make sure to burin the Xsigo driver to the the card

/opt/xsigo/bin/xg_config

########################################################################
# Main menu

Next install the ib driver

rpm -ivh kernel-ib-1.5.5.151-2.6.39_200.24.1.el5uek.x86_64.rpm

reboot — -r

Next install the Xsigo host driver

rpm -ivh xsigo-hostdrivers-kmod-2.6.39_400.19.1.el6uek.5.0.7.LX-native.x86_64.rpm

You might need to modify the /etc/init.d/xsigo to load the correct drivers for your kernel

From

/sbin/modprobe xscore boot_flag=0 system_id=3239373537335355453033344e334248

To

/sbin/modprobe /lib/modules/`uname -r`/kernel/drivers/infiniband/ulp/xsigo/xscore boot_flag=0 system_id=3239373537335355453033344e334248

Or you might fix(link) your kernel with the kernel xsigo uses

cd /lib/modules/

ln -s 2.6.39-400.19.1.el6uek.x86_64 2.6.39_400.19.1.el6uek.x86_64