Error message
xillybus: pci_enable_device() failed. Aborting.Meaning
The failure of a crucial stage in the initialization of a PCIe device causes this error message. Unless previous error messages imply that the hardware is in a shaky state, this should never happen.
Recommended action
This error should be reported, if it appears on a just booted system with FPGA just configured.
To get Xillybus working again, power the computer off, reconfigure the FPGA and power the computer on again.