I'm having a problem with a VMware ESXi server. It's running vCenter Server 5.1 and I'm trying to enable USB passthrough by configuring advanced settings on the host to select the USB controller I want to enable for passthrough. Initially, I would tick a controller and click OK and it just wouldn't show in the list of devices configured for passthrough (as per the screenshot below) even after rebooting the host.
We discovered that this is apparently a bug in ESXi 5.1.
We found on a forum that the latest update (update_01 - build 1064983 – 25 April 2013) would supposedly fix the problem. I performed an update as opposed to an install (the install option appears to change settings) of the latest build which installed successfully. I must however add that the instructions say to put the server into maintenance mode when doing the update. I forgot to do this (though all the virtual machines were powered off) but it still updated properly. After seeing no change in behaviour I performed the update again in maintenance mode which also successfully updated. Now when adding the device it will show in the list of configured devices, but after the required host reboot it's gone again. I have this setup at another client running vCenter 5.0.0 with no problem.