From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vamsi Samavedam Subject: Re: [PATCH net-next] qmi_wwan: set FLAG_SEND_ZLP to avoid network initiated disconnect Date: Thu, 14 Dec 2017 13:39:59 -0800 Message-ID: <20171214213959.GC21058@vskrishn2-linux.qualcomm.com> References: <20171214185550.15779-1-bjorn@mork.no> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org To: =?iso-8859-1?Q?Bj=F8rn?= Mork Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:36934 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbdLNVkC (ORCPT ); Thu, 14 Dec 2017 16:40:02 -0500 Content-Disposition: inline In-Reply-To: <20171214185550.15779-1-bjorn@mork.no> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Dec 14, 2017 at 07:55:50PM +0100, Bjørn Mork wrote: > It has been reported that the dummy byte we add to avoid > ZLPs can be forwarded by the modem to the PGW/GGSN, and that > some operators will drop the connection if this happens. > > In theory, QMI devices are based on CDC ECM and should as such > both support ZLPs and silently ignore the dummy byte. The latter > assumption failed. Let's test out the first. > > Signed-off-by: Bjørn Mork > --- > I am a bit worried about the effect of this change on all the > devices I can't test myself. But trying it is the only way we > can ever find out.... flag zlp is tested with pids: 9034,9048,904c,9075, 908E,9079, 908A,909F and 90A4. In general, qualcomm usb firmware can handle zlps.