From owner-freebsd-usb@FreeBSD.ORG  Mon Jan 31 20:09:15 2011
Return-Path: <owner-freebsd-usb@FreeBSD.ORG>
Delivered-To: freebsd-usb@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 92F7F1065673
	for <freebsd-usb@freebsd.org>; Mon, 31 Jan 2011 20:09:15 +0000 (UTC)
	(envelope-from hselasky@c2i.net)
Received: from swip.net (mailfe04.c2i.net [212.247.154.98])
	by mx1.freebsd.org (Postfix) with ESMTP id ECDB78FC28
	for <freebsd-usb@freebsd.org>; Mon, 31 Jan 2011 20:09:14 +0000 (UTC)
X-Cloudmark-Score: 0.000000 []
X-Cloudmark-Analysis: v=1.1 cv=wd7fLirDSts22yawIUsTeMUS9lsm8Llc0grT6RvpTjU=
	c=1 sm=1 a=DlwoGyT1WMYA:10 a=Q9fys5e9bTEA:10 a=CL8lFSKtTFcA:10
	a=i9M/sDlu2rpZ9XS819oYzg==:17 a=Khi5utXuRSRsX35rhOYA:9
	a=_S76S7SXYRGKfTf6kterCfJwyOIA:4 a=PUjeQqilurYA:10
	a=KuE2L7MIs43UQQDi:21 a=3Af9CkcodQXXnU84:21
	a=i9M/sDlu2rpZ9XS819oYzg==:117
Received: from [188.126.198.129] (account mc467741@c2i.net HELO
	laptop002.hselasky.homeunix.org)
	by mailfe04.swip.net (CommuniGate Pro SMTP 5.2.19)
	with ESMTPA id 81168141; Mon, 31 Jan 2011 21:09:13 +0100
From: Hans Petter Selasky <hselasky@c2i.net>
To: freebsd-usb@freebsd.org
Date: Mon, 31 Jan 2011 21:09:15 +0100
User-Agent: KMail/1.13.5 (FreeBSD/8.2-PRERELEASE; KDE/4.4.5; amd64; ; )
References: <20110131195921.GA57678@server.vk2pj.dyndns.org>
	<201101312106.27351.hselasky@c2i.net>
In-Reply-To: <201101312106.27351.hselasky@c2i.net>
X-Face: *nPdTl_}RuAI6^PVpA02T?$%Xa^>@hE0uyUIoiha$pC:9TVgl.Oq, NwSZ4V"|LR.+tj}g5
	%V,x^qOs~mnU3]Gn; cQLv&.N>TrxmSFf+p6(30a/{)KUU!s}w\IhQBj}[g}bj0I3^glmC(
	:AuzV9:.hESm-x4h240C`9=w
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-15"
Content-Transfer-Encoding: 7bit
Message-Id: <201101312109.15989.hselasky@c2i.net>
Cc: ed@freebsd.org
Subject: Re: u3g(4) incorrectly returning EOF
X-BeenThere: freebsd-usb@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: FreeBSD support for USB <freebsd-usb.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-usb>,
	<mailto:freebsd-usb-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-usb>
List-Post: <mailto:freebsd-usb@freebsd.org>
List-Help: <mailto:freebsd-usb-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-usb>,
	<mailto:freebsd-usb-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 31 Jan 2011 20:09:15 -0000

On Monday 31 January 2011 21:06:27 Hans Petter Selasky wrote:
> On Monday 31 January 2011 20:59:21 Peter Jeremy wrote:
> > I use a Huawei E176 on FreeBSD 8.1 for portable 3G connectivity.
> > Occasionally, ppp(8) reports:
> > Phase: deflink: read (2): Got zero bytes
> > Phase: deflink: open -> lcp
> > and ppp(8) brings the link down.  Trying to restart the link shows
> > that the E176 still thinks the link is up (entering 'term' and then
> > '~p' restores connectivity).  grog@ has similar problems with an E1762.
> > 
> > Can anyone suggest why u3g(4) is incorrectly reporting EOF to an
> > application?
> 
> Hi,
> 
> Try enabling u3g debugging.
> 
> sysctl hw.usb.u3g.debug=15
> 
> This might require compiling a kernel having:
> 
> options USB_DEBUG
> 
> Maybe the zero length data comes from USB. Else it is a TTY problem.


Reference:

sys/dev/usb/serial/usb_serial.c:ucom_put_data()

There is already a check there for zero length data, so I guess the problem is 
in the TTY layer.

--HPS