Why are UnsupReq, NonFatalErr, and CorrErr status asserted after power cycle or OS reboot while using the P-Tile Intel® FPGA IP for PCI Express?

You may find UnsupReq, NonFatalErr, and CorrErr status asserted after power cycle or operating system (OS) reboot when using the P-Tile Intel® FPGA IP for PCI Express.

According to the PCI Express Base specification revision 4.0 version 1.0, during enumeration of non-existent device or function, completion with UR status is sent, and UnsupReq is asserted. Meanwhile, Advisory Non-Fatal Error is determined and CorrErr and NonFatalErr are asserted.

To work around this problem, clear the UnsupReq, NonFatalErr, and CorrErr status in the PCI Express configuration space registers before checking them during data transaction.

This problem is not planned to be fixed in a future version of the Intel® Quartus® Prime Pro Edition Software.