Return-path: Received: from li235-22.members.linode.com ([173.255.225.22]:49191 "EHLO erley.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752009Ab1KSD21 (ORCPT ); Fri, 18 Nov 2011 22:28:27 -0500 Message-ID: <4EC72081.5020605@erley.org> (sfid-20111119_042830_531229_550C61BE) Date: Fri, 18 Nov 2011 22:20:33 -0500 From: Pat Erley MIME-Version: 1.0 To: Nick Kossifidis CC: Jan de Jongh , linux-wireless@vger.kernel.org Subject: Re: 802.11p implementation... References: <1320585006.11133.2.camel@jlt3.sipsolutions.net> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 11/17/2011 03:59 PM, Nick Kossifidis wrote: > 2011/11/12 Jan de Jongh: >> Nick Kossifidis writes: >> >>> >>> 2011/11/6 Johannes Berg: >>>> On Sun, 2011-11-06 at 02:53 +0200, Nick Kossifidis wrote: >>>>> It seems a group of people have released an 802.11p implementation on >>>>> top of 2.6.31. >>>>> >>>>> http://www.gcdc.net/mainmenu/Home/downloads/Technology >> ... >>>> johannes >>>> >>> >> ... >> >> Hi Nick, Johannes, >> >> First, please note that I haven't checked on recent ath5k support for 802.11p. >> If such support it already present, this mail is quite obsolete :-)... >> >> The Grand Cooperative Driving Challenge succesfully used 802.11p in >> vehicle-to-vehicle communications and vehicle-to-infrastructure communications, >> using a modified ath5k driver (which you found on the gcdc.net site). >> Apart from GCDC, there are many research and commercial projects/products >> (SPITS/FREILOT/...) using patched ath5k drivers for half-clock-rate operation, >> ocb, and access to the 5.9-6.0 GHz frequencies. >> And there are many more to come,. >> Simply because Atheros-based cards are among the few >> (if not the only ones) >> that support 802.11p/5.9GHz operation. >> For GCDC, the patches had their origins in the CVIS project, >> and in work by Eric Koenders of Peek Traffic. >> >> However, the current situation is far from ideal... >> By now, the 11p amendment has been ratified, >> but maintaining 802.11p support for contemparory kernel/compat-wireless combos >> is near to impossible without structural support from ath/ath5k developers. >> The result of this effort, in short, would mean 802.11p operation >> through module parameter and crda/regdb settings only, >> and without the need to (re)compile kernels and/or kernel modules. >> 11p Operation would simply imply some configuration efforts >> on well-known distributions (modules,conf, regdb/crda, iw, and stuff like that) >> out-of-the-box... >> I understand that there are regulatory issues >> (crda, do we want anyone to operate on the ITS frequencies???) involved, >> but we would be very interested in >> structural 11p support in the ath5k driver (and, perhaps ath9k). >> "We" referring to a substantial part of the ITS community. >> If you can arrange substantial commitment to 11p support in ath5k, >> I can mobilize people and funding for >> development/testing/deployment/discussion/feedback. >> >> Let me know what you think of this, best wishes, >> >> Jan de Jongh >> GCDC - Technology Leader >> > > ath5k already has half/quarter width channel support, we just don't > have an interface for it yet (we 'll add one through debugfs soon). > What else do you need from the driver and the protocol stack ? From a > quick look at the patches you use, you only want half width channel > support and to disable beacons by setting beacon interval to 0. Is > that all ? > > Also your patches on ath5k are missing some parts, I suggest you > update your code or re-base your changes on top of a newer kernel > version to get proper half width support for more cards and more. > > Finally if you want to work with upstream developers I suggest you > send your code and comments to linux-wireless instead. > > I have a working patch I'm using (and an openwrt implementation patch). I'll resubmit them to the ath5k-devel ML monday. It works quite well. Pat Erley