Port Multiplier on SATA RAID card not working

I recently bought a Sharkoon SATA Quickport Duo


which is attached to an eSATA port on a SiliconImage SATA RAID card.

I have used this card in the past as an attachment for JBOD SATA drives, which are then assembled into a software linux RAID1 array, but now I just want to use it to connect the above device to the mainboard.

The system will only see one drive at a time. If I populate both drive bays in the Sharkoon Quickport, then neither drive is mountable.

The Sharkoon information says that two HDD operation via eSATA is only possible when the eSATA controller supports Port Multiplier. The SiliconImage website says that the card, which uses their si3124 chip, supports Port Multiplier functionality.


My kernel has the sata_sil24 module loaded.

Can anyone suggest a reason why I’m not able to activate the Port Multiplier function? Am I missing something obvious?