Return-path: Received: from mail-wi0-f173.google.com ([209.85.212.173]:58392 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752211AbaJIOGk (ORCPT ); Thu, 9 Oct 2014 10:06:40 -0400 Received: by mail-wi0-f173.google.com with SMTP id fb4so13259182wid.6 for ; Thu, 09 Oct 2014 07:06:39 -0700 (PDT) Date: Thu, 9 Oct 2014 16:06:37 +0200 From: Karl Beldan To: Johannes Berg Cc: linux-wireless , Karl Beldan Subject: Re: [PATCH] mac80211/trivial: fix typo in starting baserate for rts_cts_rate_idx Message-ID: <20141009140636.GC20644@magnum.frso.rivierawaves.com> (sfid-20141009_160644_475877_75FAC281) References: <1412690018-18429-1-git-send-email-karl.beldan@gmail.com> <1412845586.1828.27.camel@jlt4.sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <1412845586.1828.27.camel@jlt4.sipsolutions.net> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, Oct 09, 2014 at 11:06:26AM +0200, Johannes Berg wrote: > On Tue, 2014-10-07 at 15:53 +0200, Karl Beldan wrote: > > From: Karl Beldan > > Is that really trivial? It seems to have some impact on the code, but I > can't right now say exactly what the impact is. Can you describe it and > say whether I should add it to mac80211 or mac80211-next? For "trivial" > I'd probably say mac80211-next, but this might be more important than > that? > The typo is clearly showing but the faulty behavior clearly demands more detail indeed. It affects non-(V)HT rates and can lead to selecting an rts_cts rate that is not a basic rate or way superior to the reference rate (ATM rates[0] used for the 1st attempt of the protected frame data). E.g, assuming the drivers register growing (bitrate) sorted ieee80211_rate tables, having : - rates[0].idx == d'2 and basic_rates == b'10100 will select rts_cts idx b'10011 & ~d'(BIT(2)-1), i.e. 1, likewise - rates[0].idx == d'2 and basic_rates == b'10001 will select rts_cts idx b'10000 The first is not a basic rate and the second is > rates[0]. I hope it clarifies things enough. Karl