On Wed, 4 Mar 2015, temp sha wrote: > Hi, > > Is it necessary to use xHCI driver for USB 3.0 host controller? A USB-3 host controller _is_ an xHCI controller. Obviously it is necessary to use the xhci-hcd driver to drive an xHCI controller. > I am > trying to support Transdent PNU3 (having usb 3.0 controller) in my h/w > running 2.6.16 kernel. Is it not > possible to use other legacy host controllers (ohci/uhci/ehci) already > available in 2.6.16 kernel ? You are using the wrong words. The 2.6.16 kernel doesn't contain legacy host _controllers_ -- it contains legacy _drivers_. Those drivers are capable of handling legacy hardware. If your PNU3 system has only an xHCI controller (no OHCI, UHCI, or EHCI controllers) then the legacy drivers won't do any good. > Will usb 3.0 not fallback to usb 2.0 > with legacy drivers ? No; it falls back with legacy _devices_. But an xHCI controller cannot be handled by legacy drivers, even though it can communicate with legacy devices. > I do not want to put my effort back-porting xhci > to old kernel until it is absolutely necessary. As Greg said, you will be better off putting your effort into getting a current kernel to work with your hardware. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
