Agilex 7 R-Tile RBES FPGA – CXL Device Enumeration Failure with CXL IP Design Example

1. What is the failure symptom? Please elaborate on the failure symptoms in detail.
The CXL device fails to enumerate when using the CXL Type-3 IP design example.
•    lspci -vvv | grep 0ddb does not detect the CXL device
•    numactl -H does not report a CXL NUMA node
The issue persists across multiple system reboots and bitstream rebuilds. A factory reset was attempted but did not resolve the issue.

2. When did the failure happen? When did you buy the part, and when did you receive it?
The device failed at some point around October 2025. 

3. How did you discover the failure? Please describe it in detail.
We found OS failed to find the CXL device and confirmed the issue after factory recovery.  

4. In which part of your process did you find the issue (Lab, production, quality, etc.)?
Lab environment.4.1 Was the device already in the field? How many times has it been used?
No. The device has only been used in a controlled lab environment for bring-up and testing.

5. How many units failed and how many units were used/tested by you? Which is the production code?
•    Failed units: 1
•    Units tested: Multiple Agilex FPGA boards
•    Production code: Not available
Only this unit exhibits the failure.

6. How did you determine the failure? Please elaborate on the procedures.
Multiple bring-up attempts were conducted using known-good hardware, software, and bitstreams.
•    6.1 Internal Debug: No internal physical failure analysis was performed.
•    6.2 Device Swap: Yes. Replacing the board with a known-good FPGA resolves the issue.

7. Was the failing unit ever working before the failure?
Yes. The device was functioning correctly before the failure.

8. How did you rule out electrical overstress (EOS) or electrostatic discharge (ESD)?
There is no visible physical damage on the FPGA or PCB.
The board has been handled according to standard ESD-safe lab procedures.

9. What are your expectations from this failure analysis?
Identify the root cause of the failure and restore proper CXL IP functionality, or provide a replacement device.

10. Have you re-balled your device? If yes, was it lead-free reballing?
No. The device has not been re-balled, and no third-party rework was performed.

11. Please add pictures of the device from the top and the bottom. See attached. 

12. Is there any other relevant information that could assist in the failure analysis?
No additional information at this time.

13. Are there any known changes to the process, materials, or design that could have contributed to the failure?
No.