If you run sudo lspci -vvvv | grep -i plx you’ll get a listing of all the relevant PCI bridges. For example, 19:08.0. Then you can go through each one with sudo lspci -s 19:08.0 -vvv | grep -i acs and look at the ACSCtl line (the last line of output). All of the flags should have  a - sign on them. If not, you can set them appropriately with sudo setpci -s 19:08.0 f2a.2=0000. Once you’ve done this for all of them, you should be able to use DataParallel.