From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail30s.wh2.ocn.ne.jp ([125.206.180.198]:40068 "HELO mail30s.wh2.ocn.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752869Ab0DLIek (ORCPT ); Mon, 12 Apr 2010 04:34:40 -0400 Received: from vs3012.wh2.ocn.ne.jp (125.206.180.183) by mail30s.wh2.ocn.ne.jp (RS ver 1.0.95vs) with SMTP id 2-0783751278 for ; Mon, 12 Apr 2010 17:34:38 +0900 (JST) From: Bruno Randolf To: Johannes Berg Subject: Re: [PATCH 2/2] mac80211: Initialize IBSS basic rates according to band Date: Mon, 12 Apr 2010 17:34:39 +0900 Cc: linville@tuxdriver.com, linux-wireless@vger.kernel.org References: <20100412073658.28078.32155.stgit@tt-desk> <201004121658.09189.br1@einfach.org> <1271059801.3877.5.camel@jlt3.sipsolutions.net> In-Reply-To: <1271059801.3877.5.camel@jlt3.sipsolutions.net> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Message-Id: <201004121734.39700.br1@einfach.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Monday 12 April 2010 17:10:01 Johannes Berg wrote: > On Mon, 2010-04-12 at 16:58 +0900, Bruno Randolf wrote: > > On Monday 12 April 2010 16:41:22 you wrote: > > > On Mon, 2010-04-12 at 16:37 +0900, Bruno Randolf wrote: > > > > When we create an IBSS we are can define the basic rates according to > > > > the band in use. Previously only the B mode rates (1 and 2Mbps) were > > > > used unconditionally, which resulted in low thruput when using > > > > RTS/CTS. > > > > > > > > Also we should save the IBSS basic rates configuration when we join > > > > an IBSS. > > > > > > Again, this breaks things. If you feel this is necessary for some > > > reason, it needs to be configurable during the IBSS join by userspace. > > > > without the previous patch (which you NACKed) this is still the correct > > thing to do in B mode and will result in only 1Mbps as a basic rate. > > without this patch it is definetly wrong for A mode. > > No, you don't understand. It will break _talking to_ 11b only stations > when the local station is 11g capable. i understood that this is what you mean. note that i said *without* the other patch! the first patch breaks talking to 11b only stations, true. the second doesn't because: as it is now ieee80211_mandatory_rates(local, sband->band) returns 1 (1Mbps) in a 2GHz channel. which is o.k. for B only stations. before we unconditionally used 3 (1Mbps, 2 Mbps) as basic rates. this clearly is wrong in the 5GHz band. > > i can see the reason why you refused the first patch, but the main > > problem is that there is no clear distiction between B and G in > > mac80211. there needs to be a way to configure B-only, G-only and BG ERP > > mode. i don't believe this is applicable to IBSS mode only... is it? > > It is, as far as I can tell. And mesh maybe. > > > btw: why is only 1Mbps used as a basic rate in B mode in > > set_mandatory_flags_band()? i think 2Mbps should be there as well? > > Not sure, could be a bug? maybe... unfortunately i can't find a clear definition of basic rates in the 11b standard, but usually 1 and 2Mbps are used. for b/g compatibiliy i've seen 1, 2, 5.5, 11 used as basic rates - i think that's what most APs do. > > anyhow, i wouldn't mind adding something to configure this from > > userspace. can you point me to the right direction? i mean i can add > > something to IBSS setup but as i said i can't believe this is only > > relevant to IBSS mode. > > What other modes do you think it is relevant to? i'm not so familiar with the way STA and AP operate, but i thought that also there the distiction between B, B/G and pure-G could make sense. if not i'll just add code to the IBSS setup... bruno