Agilex™ 7 M-Series Known Issue List

ID 851750
Date 8/27/2025
Public
Document Table of Contents

2.1.1.14. F-Tile 400G Ethernet Altera® FPGA Hard IP RX Priority Flow Control Issue

Description

When using the F-Tile 400G Ethernet Altera® FPGA Hard IP variant with Priority Flow Control (PFC) enabled, the 400G RX MAC might incorrectly turn a priority queue from the XOFF state to the XON state under all of the following conditions:

  • The RX MAC receives 2 back-to-back PFC frames with no other type of Ethernet frame between them
  • The second PFC frame is sent before the quanta of the first PFC frame expires
  • The Priority Enable Vector (PEV) of the second PFC frame has some of the same classes enabled as the first PFC frame
  • The packet arrangement on the RX MAC MII interface is such that the second PFC frame’s PEV and End-of-Packet appear in the same MII clock cycle

Workaround

None

Status

Table 17.  Device Status Table
Devices Affected Planned Fix
  • AGMx0xxR47Axxxx
  • AGMx0xxR31Bxxxx
  • AGMx0xxR47Bxxxx
Future release of Quartus® Prime Pro Edition software