I am trying to hook up 27 USB device to an Intel NUC running CentOS 7 but no matter what I do the system can never see more than 20. I have tried multiple models of NUCs and even tried adding an extra mPCIe USB controller card to one, I tried a 1U server with an Intel Xeon and an extra PCIe USB controller card, and even tried a Mac Mini. The Mac Mini was able to recognize the most devices at 20 but this is still shy of what we need. The extra USB controller cards made no difference in the number of devices the system recognized. The 27 devices are spread across 3 powered 10 port hubs. Does anyone know why the systems would not be able to see all of the USB devices since even with the hubs it is still way under the 127 USB spec limit?
Thanks for the help!