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Re: PCMCIA USB2.0 Card

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.

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