Why is there invalid data on the rx_avs interface of Serial Lite IV Intel® FPGA IP on Intel Agilex® 7 devices and Intel® Stratix® 10 devices?

Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 21.4 and earlier, you might see invalid data on the rx_avs interface of Serial Lite IV Intel® FPGA IP if you reset its link partner Serial Lite IV Intel® FPGA IP.  

The following is an example waveform capture for invalid data:

1. rx_avs_data will toggle, containing some random data.
2. rx_avs_valid will toggle, but no sop/eop asserted when rx_avs_valid is high.
3. rx_link_up will go high with unexpected random data and valid indication. rx_error shows a PCS error.

To fix this problem, download and install the following patch:

• Intel® Quartus® Prime Pro Edition Software v21.4 Patch 0.69 for Linux (quartus-21.4-0.69-linux.run)
• Intel® Quartus® Prime Pro Edition Software v21.4 Patch 0.69 for windows (quartus-21.4-0.69-windows.exe)
• Readme for Intel® Quartus® Prime Pro Edition Software v21.4 Patch 0.69 (quartus-21.4-0.69-readme.txt)

This problem is scheduled to be fixed in a future release of Intel® Quartus® Prime Pro Edition Software.