Re: [Libusb-devel] USB 2.0

[Peter S. <stu...@cd...>]

On Thu, Mar 29, 2007 at 10:36:06AM -0700, Tim Roberts wrote:
> Peter Stuge wrote:
> >
> > The EHCI should provide a number of [UO]HCI PCI devices for USB 1.1
> > devices, so this should just be a matter of blocking/disabling the
> > EHCI driver.
> 
> Do you have evidence that this really works?  I thought the UHCI
> drivers came to life as children of the EHCI driver, not
> necessarily as independent hardware entities.  However, I admit
> that I haven't tried it.

I think I've tried it, although it was by mistake. I didn't have the
EHCI driver and could still use a USB memory stick, just very slowly.

lspci reports the UHCI controllers separately.

--8<-- Also from page 3 of EHCI 1.0 spec
A USB 2.0 Host Controller includes one high-speed mode host
controller and 0 or more USB 1.1 host controllers (see Figure 1-2).
The high-speed host controller implements an EHCI interface. It is
used for all high-speed communications to high-speed-mode devices
connected to the root ports of the USB 2.0 host controller. This
specification allows communications to Full- and Low-speed devices
connected to the root ports of the USB 2.0 host controller to be
provided by companion USB 1.1 host controllers. If an implementation
does not include companion host controllers, the host controller must
include a high-speed device permanently attached to each of the EHCI
ports the implementation is planning to utilize. The EHCI controller
cannot work with a Full- or Low-speed device.
-->8--


//Peter