KCU105 Build Error: [Place 30-1114] Floating OSERDES ODDRE1_1 is not placed

Hello! I am trying to build the bitstream for the KCU105 board using ./make.py --board=kcu105 --cpu-count=4 --build, however, it fails in the place design step like so:

19 Infos, 1 Warnings, 0 Critical Warnings and 10 Errors encountered.
place_design completed successfully
place_design: Time (s): cpu = 00:07:28 ; elapsed = 00:03:50 . Memory (MB): peak = 3580.902 ; gain = 16.008 ; free physical = 3456 ; free virtual = 8132
ERROR: [Common 17-39] 'place_design' failed due to earlier errors.

    while executing
"place_design -directive default"
    (file "kcu105.tcl" line 46)
INFO: [Common 17-206] Exiting Vivado at Wed Jul  7 14:15:02 2021...
Traceback (most recent call last):
  File "./make.py", line 662, in <module>
    main()
  File "./make.py", line 640, in main
    builder.build(run=args.build, build_name=board_name)
  File "/home/garrett/Litex/litex/litex/soc/integration/builder.py", line 293, in build
    vns = self.soc.build(build_dir=self.gateware_dir, **kwargs)
  File "/home/garrett/Litex/litex/litex/soc/integration/soc.py", line 1113, in build
    return self.platform.build(self, *args, **kwargs)
  File "/home/garrett/Litex/litex/litex/build/xilinx/platform.py", line 53, in build
    return self.toolchain.build(self, *args, **kwargs)
  File "/home/garrett/Litex/litex/litex/build/xilinx/vivado.py", line 355, in build
    _run_script(script)
  File "/home/garrett/Litex/litex/litex/build/xilinx/vivado.py", line 101, in _run_script
    raise OSError("Error occured during Vivado's script execution.")
OSError: Error occured during Vivado's script execution.

I reran it in the Vivado GUI using the commands from the kcu105.tcl file and it gave me 10 errors after failing the place design step again:

[Place 30-1114] Floating OSERDES ODDRE1_1 is not placed and is not a part of any Shape. It won't be placed by the IO Placer.

Repeating with OSERDES ODDRE1_(2-9) After looking up similar issues, I suspect it might have something to do with my Vivado version or perhaps my Ubuntu version. I have used both Vivado 2020.2 and 2018.1 on Ubuntu 20.04.2 LTS 64-bit.

Edit: I have also tried it on Vivado 2019.1 and Ununtu 18.04

[joshuadenis]

This is a bit late, but I’ve run into the same problem. After a lot of digging around, and piecing together different resources (Don’t have all the links anymore, sorry), what worked for me was modifying the script that generates the build instructions for Vivado.

In the file litex/litex/build/xilinx/vivado.py at line 230 in the placement section right before the line tcl.append(“place_design -directive {}”.format(self.vivado_place_directive)), I added tcl.append(“place_ports”). Everything now builds correctly.

I am running Vivado 2018.1 on Ubuntu 21.04.

Hope this helps!

[enjoy-digital]

Thanks @AEW2015 for the fix, this has been integrated in LiteX: https://github.com/enjoy-digital/litex/commit/9f75c73d6ba9a86fd4479b7f8666ae619bf1d1a3. The issue was introduced by the use of SDRTristate in LiteSDCard.