From: Dan Williams Subject: Re: [PATCH] CDC_NCM adding support IFF_NOARP for infineon modem platform Date: Mon, 14 Jan 2013 11:19:13 -0600 Message-ID: <1358183953.1713.28.camel@dcbw.foobar.com> References: <1357990479-5836-1-git-send-email-cpuwolf@gmail.com> <20130112.153533.1713284383322153346.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: cpuwolf@gmail.com, gregkh@linuxfoundation.org, alexey.orishko@stericsson.com, bjorn@mork.no, linux-usb@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45924 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756522Ab3ANRQn (ORCPT ); Mon, 14 Jan 2013 12:16:43 -0500 In-Reply-To: <20130112.153533.1713284383322153346.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Sat, 2013-01-12 at 15:35 -0800, David Miller wrote: > From: Wei Shuai > Date: Sat, 12 Jan 2013 19:34:39 +0800 > > > Infineon(now Intel) HSPA Modem platform NCM cannot support ARP. so I > > introduce a flag CDC_NCM_DRIVER_DATA_NOARP which is defined in > > driver_info:data. so later on, if more such buggy devices are found, > > they could use same flag to handle. > > Is it no able to do ARP or, the more likely case, does broadcast > not work at all? > > If it's the latter, IFF_NOARP is just making over the real problem. > > I'm not applying this, no hardware device should set IFF_NOARP. > You probably really want IFF_POINTOPOINT or similar. IFF_NOARP is already done for other WWAN devices (sierra_net, hso, cdc-ether, cdc-phonet, lg-vl600, etc) so there is some precedent. Some drivers (phonet, hso) set *both* POINTTOPOINT and NOARP. Is that redundant, and should all WWAN drivers be moved to only POINTTOPOINT? (aside: usbnet has FLAG_POINTTOPOINT, but that's nothing to do with IFF_POINTTOPOINT, it only controls whether the interface is named usbX or ethX. Confusing.) Dan