Why is there a mismatch in Priority Flow Control (PFC) frame duration using the F-Tile Ethernet Hard IP variant configured for 400GE-8 or 400GE-4?

Description

Due to a problem in the Quartus® Prime Pro Edition software version 24.3, you may see the o_rx_pfc signal shows an incorrect duration that doesn’t match the received PFC control frame quanta values when back-to-back PFC frames are received on RX-MAC in the F-Tile Ethernet Hard IP using 400GE configurations.
The incorrect duration is seen because of a problem in the F-Tile Ethernet Hard IP, where PFC indication is cleared in just 2-3 HIP cycles instead of maintaining the proper duration based on the received frame’s quanta field. This occurs only in 400GE configurations. 

Resolution

There is a workaround implemented to handle PFC indication soft logic within the F-Tile Ethernet Hard IP.
If you may need this workaround for the previous Quartus Prime Pro Edition software, please contact an Altera Representative and quote ID #15017410220.
This problem is scheduled to be fixed in a future release of the Quartus® Prime Pro Edition software.