Error message
xillybus: No support for IDT version X. Aborting.Meaning
This error indicates that the Xillybus IP core in the FPGA is of a version newer than the host driver's. Since there is only one IP core version released at this time (including custom IP cores), this condition is never expected to happen, and most likely indicates unreliable hardware (e.g. FPGA timing constraints set up improperly).
If this error appears in conjunction with other fatal errors, they may give the reason.
Recommended action
This is most likely not an issue with the Xillybus core itself, but may very well be related to improper timing constraining or a poor system clock. The FPGA should be checked for causes of unreliable operation.
Normal operation may be achieved by unloading and reloading the Xillybus kernel module.