Troubleshooting¶

SSD failures¶

If you test the SSD using the standalone application of this reference design, and you cannot get link-up, you can try the following:

If you are using the AXI Bridge for PCI Express Gen3 Subsystem IP (VC709, KCU105), open the project in Vivado, then open the IP configuration for PCIe. There is a tab called “GT Settings” that contains a “Receiver Detect” setting. Change this setting to “Falling Edge”, then save and rebuild the design. Some SSDs require this setting to link up correctly.
If your SSD has both the B and M keys, then it only has 2x PCIe lanes rather than 4x. In order for a 4-lane PCIe block to operate with a 2-lane SSD, it needs to downshift during the link width negotiation. The Xilinx PCIe blocks support downshifting, however the lanes need to be properly assigned in order for this to work properly. If you are using an SSD with both the B and M keys, and you are not getting link-up, then we suggest you validate the lane assignment in the constraints file with respect to your schematic drawings. If your constraints seem correct, and it is still not working, then we suggest you reverse the lane order assignment in the constraints file (downshifting only works properly if the lane ordering is correct). Alternatively, you can try reconfiguring your PCIe IP for 2 lanes, rather than 4, in which case you would also need to adjust your constraints.

Check the following if the project fails to build or generate a bitstream:

Are you using the correct version of Vivado for this version of the repository?

Check the version specified in the Requirements section of the README.md file. Note that this project is regularly updated and you may have to refer to an earlier commit of this repo if you are using an older version of Vivado.
Did you correctly follow the build instructions?

Please check the build instructions carefully as you may have missed a step.
Did you copy/clone the repo into a short directory structure?

Windows doesn’t cope well with long directory structures, so copy/clone the repo into a short directory structure such as C:\projects\. When working in long directory structures, you can get errors relating to missing files, particularly files that are normally generated by Vivado (FIFOs, etc).