From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felix Date: Mon, 27 Sep 2010 13:32:54 -0700 Subject: [ath9k-devel] [AR9160]: 3 RX chain operation in 11abg legacy-only mode? In-Reply-To: <20100927193307.GH2429@tux> References: <20100927181952.GC2429@tux> <1285615536.14149.5.camel@darkslate> <20100927193307.GH2429@tux> Message-ID: <1285619574.14149.9.camel@darkslate> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ath9k-devel@lists.ath9k.org On Mon, 2010-09-27 at 12:33 -0700, Luis R. Rodriguez wrote: > On Mon, Sep 27, 2010 at 12:25:36PM -0700, Felix wrote: > > On Mon, 2010-09-27 at 11:19 -0700, Luis R. Rodriguez wrote: > > > On Sat, Sep 25, 2010 at 08:14:43PM -0700, Adrian Chadd wrote: > > > > Hi, > > > > > > > > FreeBSD's AR9160 support enables all three RX chains in legacy mode. > > > > The ath9k codebase doesn't - it calibrates all three chains, but the > > > > ADC calibration results in legacy mode give all 0x0's for chain 1 and 2. > > > > (And seemingly invalid results for chain 0 in 11g mode, but that's another > > > > issue which I am hoping someone will comment on.) > > > > > > > > Is there any benefit or detriment to leaving RX chains 1 and 2 enabled > > > > when in 11a/11bg mode? Does the unit do any kind of multipath > > > > discrimination? > > Leaving all RX chains enabled will give a huge gain for all OFDM rates, > > they get MRC combined > > (http://en.wikipedia.org/wiki/Maximal-ratio_combining) in the frequency > > domain(after the FFT). > > Interesting, thanks Felix, I suppose this may be applicable to > carl9170 as well then, think it uses the same radio? Anyway > patches welcomed. Correct. Felix