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Date:      Wed, 27 Feb 2013 22:51:12 +0200
From:      Aleksandr Rybalko <ray@freebsd.org>
To:        Adrian Chadd <adrian@freebsd.org>
Cc:        freebsd-arm@freebsd.org, Brett Wynkoop <wynkoop@wynn.com>, Ian Lepore <ian@freebsd.org>
Subject:   Re: Raspberry Pi Network Data
Message-ID:  <20130227225112.b480823a.ray@freebsd.org>
In-Reply-To: <CAJ-VmonGg_koZ%2Be6OogM0Hp%2BZa8obKhfqFBkL5yBwF_mPpO1Yw@mail.gmail.com>
References:  <20130226120335.6928b473@ivory.wynn.com> <BAY165-ds1973AAF7E1EBE7F0B444D6CAFC0@phx.gbl> <1361904727.16937.133.camel@revolution.hippie.lan> <20130226224901.04164f9d.ray@freebsd.org> <CAJ-VmonGg_koZ%2Be6OogM0Hp%2BZa8obKhfqFBkL5yBwF_mPpO1Yw@mail.gmail.com>

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On Tue, 26 Feb 2013 13:56:43 -0800
Adrian Chadd <adrian@freebsd.org> wrote:

> On 26 February 2013 12:49, Aleksandr Rybalko <ray@freebsd.org> wrote:
> 
> > Hello ARM hackers!
> >
> > Guys, connect please RPi to good, standalone 5V powers supply (1-2A
> > will be enough) instead of USB port of something. That will close
> > most problems, at least Ian's problem :-D
> 
> Sure! But the side question is - can the error handling be improved?
> It's coming/going and that's fine; but can the reattach be made more
> reliable?

It will be very nice, but I have only one idea which may help somehow,
it is check current and voltage on all ports if hub or phy support
that. But there is too much troubles:
* Most embedded devices connect USB +5V line directly to main supply
bus;
* Most controllers have only OVER_CURRENT flag, so you can't calculate
total power consumption or get voltage level on rail;
* We need to know power source parameters.

So we don't know how that consumption affect system as result we have
voltage lower than minimum required in main system (lost bits, then
fault and reboot) or in attached USB device (just device lost).

So I see no way to detect that properly :(

Maybe Hans can give some hints?

> 
> 
> 
> Adrian


-- 
Aleksandr Rybalko <ray@freebsd.org>



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