lkml.org 
[lkml]   [2008]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH 3/3] USB: driver for Freescale QUICC Engine USB Host Controller
Date
On Wednesday 24 September 2008, Sergei Shtylyov wrote:
>
> >>   ... 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...

Only the OHCI registers have bit positions matching what the USB
spec says for hub status bits. Everything else, including musb_hdrc,
has the relevant status encoded in other bits.


> I looked at the core and figured that USB core seems to use the root hub
> interface for port PM, etc. and expects it to bee present, so it seems
> unavoidable indeed... :-/

Or more fundamentally: for enumeration. "Unavoidable" is correct. ;)

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2008-09-24 21:01    [W:0.268 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site