On my ESXi 6.0 server (a Dell T5500), I can successfully passthrough PCI/PCIe connected devices (e.g., GPU, audio, USB card) without any issues. However, when I try to pass through any devices present on the motherboard (onboard USB or audio, for example), I am unable to use the device in the assigned VM.
Is this a typical problem? Is it a peculiarity of the T5500 or the chipset (Intel 5520 I think)?