From: David Brownell <david-b@pacbell.net>
To: linux-usb-devel@lists.sourceforge.net
Cc: "Mike Frysinger" <vapier.adi@gmail.com>,
gregkh@suse.de, Robin Getz <rgetz@blackfin.uclinux.org>,
linux-kernel@vger.kernel.org
Subject: Re: [linux-usb-devel] [PATCH] : Allow embedded developers USB options normally reserved for OTG
Date: Wed, 2 Jan 2008 11:16:28 -0800 [thread overview]
Message-ID: <200801021116.29067.david-b@pacbell.net> (raw)
In-Reply-To: <8bd0f97a0801021058g15d32de7nd29102ec552ba5fa@mail.gmail.com>
On Wednesday 02 January 2008, Mike Frysinger wrote:
> > >
> > > Allow embedded developers to turn support for USB Hubs off even if they have a
> > > full root hub. This saves the overhead (RAM and Flash size).
> >
> > ISTR that it won't save very much code though ... the Linux USB
> > stack structures all its enumeration logic around hubs.
>
> perhaps the code size is arguable as to whether it really matters.
> the reason we want it is that we have a USB host controller that will
> not work with USB hubs, so we want to make sure the system does not
> attempt such things. (yes, such a USB host controller is retarded,
> but the decision was out of our hands.)
Well, it won't work with *external* hubs. Root hubs are a different
story. :)
I think that's one of a class of decisions sometimes made by folk
who need to conserve silicon real estate. Supporting external hubs
has always been optional for OTG systems.
- Dave
next prev parent reply other threads:[~2008-01-02 19:16 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-02 14:48 [PATCH] : Allow embedded developers USB options normally reserved for OTG Robin Getz
2008-01-02 18:47 ` [linux-usb-devel] " David Brownell
2008-01-02 18:57 ` Felipe Balbi
2008-01-02 19:14 ` David Brownell
2008-01-02 18:58 ` Mike Frysinger
2008-01-02 19:16 ` David Brownell [this message]
2008-01-02 19:46 ` Alan Stern
2008-01-02 20:25 ` David Brownell
2008-01-02 20:58 ` Alan Stern
2008-01-03 3:50 ` David Brownell
2008-01-03 3:52 ` Bryan Wu
2008-01-03 17:01 ` Richard D
2008-01-03 3:03 ` Robin Getz
2008-01-03 3:43 ` David Brownell
2008-01-03 4:40 ` Bryan Wu
2008-01-03 7:36 ` David Brownell
2008-01-03 8:05 ` Bryan Wu
2008-01-03 17:04 ` Richard D
2008-01-04 1:20 ` Robin Getz
2008-01-03 7:58 ` Robin Getz
2008-01-03 3:47 ` Bryan Wu
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