[usb] Questions about Root HUB

["Àî9370" <li9370@sina.com>]

Hi,friends
I am a post gradutate student majored in Microelectronics. I am designing the USB Host Controller according to the OHCI1.0 Spec. Now I am very confused by some questions.
Q1)Is the UsbReset state of HC used to reset the root hub?
Q2)Will the state of all the down stream ports of the root hub be the disconnected state when HC is in UsbReset state? 
Q3)What's the meaning about "When in the USBRESET state,the Host Controller forces reset signaling on the bus"? will all the downstream ports of the root hub be reset?
Q4)Is the USBSUSPEND state of the HC used to suspend the whole usb system?
Q4)What's the purpose of the software reset in HC? to reset the registers and all the state machines in the HC? if so then how to understand  "Following a software reset, the Host Controller Driver may cause a transition to USBOPERATIONAL if the transition
occurs no more than 1 ms from the transition into USBSUSPEND"? shouldn't the registers in the HC be reconfigured after the software reset?befor the reconfiguration to the registers how can transitioning to USBOPERATIONAL?
Thanks for reading the long query. Please share your thoughts
on above queries.

with regards,
Hubert
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