Re: [PATCH] Fix OTG HNP for hub.c (USB OTG HNP (can you find any other appropriate TLAs?)

On 5/30/07, Tony Lindgren <[email protected]> wrote:
> * David Brownell <[email protected]> [070529 16:04]:
> > On Tuesday 29 May 2007, Tony Lindgren wrote:
>
> <snip snip snip snip>
>
> > > - Enable HNP "early" (later would be OK too);
> > > - Offer to do HNP if the peripheral wants to use it
> >
> > Host doesn't know anything about "peripheral wants";
> > from its perspective, this is an blind offer to go
> > down the "peripheral #2" path.
> >
> >
> > >   (Peripheral maintains _both_ b_hnp_enable set by
> > >   a_host and user preference on b_device on using
> > >   b_hnp_enable)
> >
> > That "user preference" is problematic.  What do you
> > end up with if that requirement for a user choice is
> > removed ... ?
>
> How else do you tell when to use HNP then? It's the
> b-device that needs to have that configured in, and
> having HNP always enabled on b-device make sense either.
>
> I think it's designed to as a ways for b-device to
> request being a host, so it's not supposed to be automatic.
> If you want automatic host mode, then just use a-cable,
> right?

Yeah.. that's right... from my understanding it should be a user-request.
The "natural" way for changing roles would be a cable switching... but
we're lazy enough to do it.. so the the b-device requests (the user
requests) to become host during a small time-slice... we know it will
start and finish. Don't we?

>
> Anyways, I'll play with an OPT and send patches in few
> weeks, no need to do anything meanwhile unless somebody
> else is also working on HNP stuff.
>
> >
> > > ... deletia ...
> >
> > Glad to know the mechanisms are working.  But right
> > now I'm puzzled why musb_hdrc is misbehaving in
> > host mode ... it's mangling descriptors as it reads
> > them in.
>
> Which hardware? DaVinci or H4 with TUSB6010? At least
> on N800 the host mode can go through testusb -a.
>
> Tony
>


-- 
Best Regards,

Felipe Balbi
[email protected]

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