There seems to be an issue with the vhhcd.kext file and DisplayLink software. With the extension installed, my DisplayLink connected monitor blanks. Not sure which program is the issue, but I had to remove vhhcd in order to recover my DisplayLink connected monitor.
Here is the thread at the DisplayLink forum in case it is of use.
MY guess is their driver is looking for all USB Host controllers on the system and then querying them for something and the are not expecting a host controller that is not an apple built-in one. If they can tell me what they are polling for ill return what they are expecting... Since i dont interact with displaylink in any way (and actually had not heard of the company until the last few months) i suspect its in their driver.
Thanks for looking into this.
Thanks for addressing this.