I prepared a kext that will turn off only XHC0 ports without PTXH mapping, but it will work only with iMacPro1,1 SMBIOS. If you have other SMBIOS you can edit Info.plist. As to which ports will be disabled, it depends on how much ports on your mobo are derived from XHC0 - usually most of the rear ports (I lost 4). USB2.0-only and ports from headers on motherboard are usually PTXH.
A community focused on the development and support for AMD CPUs on OS X.Read more