I have a Dell SAS6/ir HBA card (pciex8), and several SATA drives. I have two SFF-8484 to 4x SATA cables, which fit correctly onto the HBA (but were purchased separately, new). The manual for the HBA is here. These are the exact cables I bought.
I connect the HBA to my motherboard, and it initializes fine. I connect the SFF-8484 whips to the HBA and the drives. I can CTRL+C into the HBA's BIOS and inspect settings; everything looks good. However, it won't detect any of the drives I plug into it; the LSI/Dell BIOS shows no devices connected (even if I browse to Advanced -> PHY devices).
What I've Tried:
I've tried connecting the drives to the onboard SATA controller on the motherboard. They work fine (which means that the drives are good, and are getting power). The cable connections to the HBA and the individual drives are fine. I've tried both of my different SFF-8484 cables, and I've tried switching the headers each cable is connected to on the HBA. Still no luck. I've tried starting the HBA with multiple drives connected, and just one (known good). Nothing. I haven't tried updating the HBA's firmware, as I don't have a computer with a floppy drive/bootable OS and a PCIe-x8 slot at present, but if I need to do that, I can.
Why isn't my HBA detecting any drives?