Re: [PATCH 3/3] USB: driver for Freescale QUICC Engine USB Host Controller

Sergei Shtylyov
2008-09-24T10:49:20Z

Hello, I wrote:

>>>>>>> This controller does not integrate the root hub, so this driver
>>>>>>> also
>>>>>>> fakes one-port hub. External hub is required to support more than
>>>>>>> one device.
>>>>>>>
>>>>>>> ...
>>>>>>>
>>>>>>>
>>>>>> Please, no.
>>>>>>
>>>>> What exactly 'no'? ;-)
>>>>>
>>>> No one-port hubs I guess -- they are pointless. Though e.g. MUSB
>>>> driver creates one -- I guess to impersonate a transaction
>>>> translating high-speed hub...
>>>>
>>>>
>>> ... then the root hub emulation is completely pointless.
>>>
>>
>> It isn't. We always should emulate the root hub. The root hub
>> is part and parcel of any USB Host. Even the one-port one.
>
> Hm, maybe that's what USB core thinks (because UHCI/OHCI/EHCI all
> have it) but e.g. MUSB doesn't have the root hub registers...

Oops, I stand corrected. Even USB 1.1 specifies that it must be a
part the host...

WBR, Sergei