Date: Thu, 9 Oct 2014 22:56:22 +0200
From: Karl Beldan <karl.beldan@gmail.com>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless <linux-wireless@vger.kernel.org>,
	Karl Beldan <karl.beldan@rivierawaves.com>
Subject: Re: [PATCH] mac80211/trivial: fix typo in starting baserate for
 rts_cts_rate_idx
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On Thu, Oct 09, 2014 at 05:22:21PM +0200, Johannes Berg wrote:
> On Thu, 2014-10-09 at 16:45 +0200, Karl Beldan wrote:
> 
> > > > 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.
> > > 
> > > Well, I'm still not sure which tree I should put it in, I guess?
> > > 
> > 
> > All I can say is that nor this faulty behavior nor the correspond fix
> > are likely to cause a crash (we always tx registered rates).
> 
> But it's still pretty misbehaving, no? That IMHO warrants fixing and
> even cc stable.
> 
Also, for the record, ATM we have only one rts_cts rate. A way to handle
every retry rates is still missing, along with (V)HT rates.
 
Karl