Are these USB devices? If they are look in /var/log/messages. You will probably see entries that the devices are detected, but the device isn't claimed by an sctive driver.
It will look like this.
usb.c: USB device 2 (vend/prod 0x3f0/0x805) is not claimed by any active driver.
If you see these lines post them. I would like to see what the "vend/prod" numbers it displays.