On Thu, 17 Mar 2005, Bob Lockie wrote:

> 4 port PCI USB2 card with 4 port hub connected:
> 
> bash-2.05b# lsusb
> Bus 003 Device 001: ID 0000:0000
> Bus 002 Device 001: ID 0000:0000
> Bus 001 Device 004: ID 05e3:0605 Genesys Logic, Inc.
> Bus 001 Device 001: ID 0000:0000
> 
> 4 port PCI USB2 card without hub:
> bash-2.05b# lsusb
> Bus 003 Device 001: ID 0000:0000
> Bus 002 Device 001: ID 0000:0000
> Bus 001 Device 001: ID 0000:0000
> 
> Maybe some can explain why there are not 4 busses (1 for each port)?

Buses aren't the same thing as ports.  Your card has 3 USB controllers
(hence 3 buses).  Probably one of them is high-speed and connects to all
four ports, while the other two are full/low-speed and are attached to two 
ports each.

It's a little confusing because high-speed buses are considered logically 
separate from full/low-speed buses, even though they communicate over the 
same cables and ports.

Alan Stern



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