Unused transceiver channels in your Intel® Stratix® 10 L- or H-Tile transceivers may degrade over time when using the Intel® Quartus® Prime software version 18.1.0 and earlier.
The Intel Quartus Prime software generates a warning message if your design contains unused transceiver channels. The warning message states that performance of unused channels may degrade over time if not properly preserved with the following Quartus Settings File (QSF) assigment.
set_global_assignment -name PRESERVE_UNUSED_XCVR_CHANNEL ON
Pin Specific Assignment
set_instance_assignment -name PRESERVE_UNUSED_XCVR_CHANNEL ON -to pin_name
For example, if PIN_U34 is used, is specified as U34 and not PIN_U34. Fitter will ignore assignment if PIN_U34 is used as <pin_name>.
In the Intel Quartus Prime software version 18.1.0 and earlier, the QSF assignment is incorrect.