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Date:   Wed, 27 Sep 2023 17:52:17 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     Tony Lindgren <tony@atomide.com>
Cc:     kernel list <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        linux-omap@vger.kernel.org, sre@kernel.org, nekit1000@gmail.com,
        mpartap@gmx.net, merlijn@wizzup.org, martin_rysavy@centrum.cz,
        phone-devel@vger.kernel.org, maemo-leste@lists.dyne.org
Subject: Re: droid4 -- weird behaviour when attempting to use usb host
Message-ID: <ZRRPsWQiTP21hozK@duo.ucw.cz>
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Hi!

> > I'm having some fun with usb host. Good news is it works with
> > externally powered hub... after a while. I get some error messages
> > about inability to go host mode, but with enough patience it
> > eventually does enter host mode and I see my keyboard/mouse.
> >=20
> > And usually in that process, one of my cpu cores disappear. top no
> > longer shows 2 cores, and I was wondering for a while if d4 is
> > single-core system. It is not, my two cores are back after reboot.
> >=20
> > That's with 6.1.9 kernel from leste. Ideas how to debug this would be
> > welcome. (Do you use usb host?)
>=20
> You are using a "proper" non-standard usb micro-b cable that grounds
> the id pin, right?

Yes.

> If not, try with one of those as it allows the hardware to do what it's
> supposed to do.
>=20
> And presumably you don't have a hacked usb hub that feeds back the
> vbus to your phone, right?

Do have hacked hub. Or more precisely, have device that needs external
power (spinning rust), and hub passes it back to the device.

I'll retry with a keyboard... but I recall it behaved funny with that, too.

> If you have, that should not be used as the pmic can feed vbus.

Well, my plan was to use it as a desktop, and external power is useful
that as Droid battery is not that big.

Best regards,
								Pavel
--=20
People of Russia, stop Putin before his war on Ukraine escalates.

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