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Re: PCMCIA USB2.0 Card

On Mon, 14 Mar 2005, Derek Broughton wrote:

> On Monday 14 March 2005 04:23, Michael Marte wrote:
> >
> > usbview tells me that there is root hub running at high speed (driven
> > by ehci) and two more hubs running at full speed (driven by ohci).
> > Interestinlgy, the full speed hubs are not children of the root hub but
> > occur on the same level of the USB device tree as the root hub. Some
> > thought and questions on this situation:
> >
> > * Why are there three hubs - not only one?
> In short, because that's the way your hardware manufacturers and software 
> configuration set it up.  My Inspiron, with two USB ports, has two hubs.  
> Doesn't seem necessary, but it's in the ACPI implementation, iirc.  The "full 
> speed" (ack!  I hate that weasel term) hubs are there because you have ohci 
> configured - why?  If you have it compiled as a module, try removing it, then 
> plugging something in - should still work, using ehci.  When you plugged in a 
> high-speed device, it bypassed the USB 1.1 hubs and went right to the 2.0 hub 
> - which makes it pretty obvious why you can't have the 1.1 hubs as children 
> of the root.
> -- 
> derek

I blacklisted ohci and, in effect, USB devices connected to either of the 
two ports are not recognized any more. I have to modprobe ohci to get them 


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