Features of the EHCI driver include:
Complies with enhanced host controller interface that supports USB 2.0.
Supports high-speed control, bulk, and interrupt transfers.
Currently, there is no support for high-speed isochronous transactions. It is possible that some USB audio devices might eventually use high-speed isochronous transactions.
If there are USB 2.0 and USB 1.x devices on the system, the EHCI and OHCI drivers hand-off device control depending upon the type of device that is connected to the system.
The USB 2.0 PCI card has one EHCI controller and one or more OHCI controllers.
A USB 1.1 device is dynamically assigned to the OHCI controller when it is plugged in. A USB 2.0 device is dynamically assigned to the EHCI controller when it is plugged in.