Disable xhci_hcd USB 3.0 module

[gregkh@linuxfoundation.org (Greg KH)]

On Mon, Dec 15, 2014 at 06:47:21PM -0200, Gustavo Duarte wrote:
> 00:14.0 USB controller: Intel Corporation ValleyView USB xHCI Host
> Controller (rev 0e)
> 
> Subsystem: CLEVO/KAPOK Computer Device 5471
> 
> Kernel driver in use: xhci_hcd

One host controller.

> Seems like here is happening you are saying, one host-controller
> (xHCI) manage the three USB port, right ?

Yes.

> May be i have a confusion, and i sorry for that, may be what i am
> asking it is impossible or may be is a blunder, any way  following is
> my thought:
> "
> I know that there are several PC, Notebooks with BIOS with the
> capability to  enable/disable xHCI USB mode, where you can choice,
> xHCI or EHCI.
> For this reason i thought that could be possible, instead  by BIOS,
> through some kernel configuration or passing a switch parameter at
> boot time achieve the same behaviour.
> "
> 
> Do you are saying that, as this notebook has only one usb
> host-controller, these option isn't possible ?

Looks like it.  But I don't know what your bios looks like, poke around
in there and see if you can find a setting like that.  I've never heard
of such a thing though.  The xhci controller is a physical chip, it
can't work like a ehci controller.

> So the only remainder way to resolve this, is trying with a new one kernel ?

To see if the bug you are having with a USB 3 device is fixed, yes.  You
will not be able to ever get the ehci driver to work with this device no
matter what kernel you change to, sorry.

greg k-h