Oracle Solaris supports all USB 3.0 devices that use the USB 3.0 xhci host controller driver, with the exception of audio devices. Backward compatibility with previous USB versions enables you to use the same hardware and software components for USB 2.0 , 1.1, and 1.0 devices on USB 3.0 ports. However, for audio devices, only USB 2.0, 1.1, and 1.0 are supported.
A single XHCI host controller supports all speeds of the USB devices. If you are using USB 2.0 ports for devices, different host controller interface drivers are dynamically assigned depending on whether those devices support USB 2.0.
For better performance, always connect USB 3.0 and USB 2.0 devices to corresponding USB 3.0 and USB 2.0 ports. A USB 3.0 or USB 2.0 port can be on any of the following components:
A USB PCI card
A USB hub that is connected to a USB port
A SPARC or x86 computer motherboard