When I use the RocketIO Architecture Wizard in receiver-only mode, RXRECCLK and RXDATA are undefined, and the hardware does not function properly.
This problem has been fixed in the 6.1i Service Pack 2, available at:
The first service pack containing the fix is 6.1i Service Pack 2.
The RocketIO Wizard does not currently connect TXUSRCLK and TXUSRCLK2 when you choose receiver-only mode. Without a TXUSRCLK clock, the receiver will not function properly.
Be sure that the TXUSRCLKs are always connected. This can be done by enabling the transmitter in addition to the receiver, and by connecting TXUSRCLK and TXUSRCLK2 to RXUSRCLK and RXUSRCLK2, respectively.
For more information, please see (Xilinx Answer 16629)