One of our ESXi 18.104.22.1681820 servers is not passing through USB devices properly despite the virtual machine having USB xHCI controller and USB controller virtual hardware. Specifically, it will only pass a USB device through if the virtual machine is powered down, the USB device is manually and freshly added as virtual hardware (if it's already added then you need to remove and add it), and the virtual machine is powered on. This is a problem when the server restarts to apply updates and the USB device gets disconnected.
To diagnose this, I enabled DirectPath I/O Configuration for the following devices but it didn't make a difference (the OS doesn't seem to even see the hardware):
Once this was done I could no longer add the USB device as virtual hardware as ESXi reported "This device cannot be added to this Virtual Machine because: There are no USB devices available on the host" so I've tried disabling DirectPath I/O Configuration for the aforementioned devices by doing the following but none have been successful:
There is one more soimilar thread in the community having the same Intel chipset . You can look into it that might help you Re: Esxi 5.1 pci passthrough broken
Thank you for the suggestions but I need to disable DirectPath I/O before I resume looking into the initial pass-through problem. Do you have any suggestions for doing so?
Also, the server is a Dell PowerEdge T320 which, according to http://www.dell.com/uk/business/p/poweredge-t320/pd, has the Intel C602 chipset.
ESXi was installed on an internal SD card.
The USB controller passthrough loop issue was resolved by reinstalling ESXi as the configuration was retained during an upgrade but this wasn't a major problem for us as all we had to do was re-setup the management network and re-add the VM's VMX from the datastore on the RAID volume to the inventory.
The original USB device passthrough issue was resolved by updating from ESXi version 5.5.0-1331820 to ESXi version 5.5.0-2068190 (update 02).