Return-path: Received: from narfation.org ([79.140.41.39]:60449 "EHLO v3-1039.vlinux.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906Ab2GFPNp (ORCPT ); Fri, 6 Jul 2012 11:13:45 -0400 From: Sven Eckelmann To: Mohammed Shafi Cc: Simon Wunderlich , ath9k-devel@lists.ath9k.org, Mohammed Shafi Shajakhan , Adrian Chadd , Marek Lindner , linux-wireless@vger.kernel.org, Gabor Juhos Subject: Re: ath9k: Problems with diversity on AR9330 Date: Fri, 06 Jul 2012 17:13:42 +0200 Message-ID: <5244861.J1Tyef1FCX@bentobox> (sfid-20120706_171349_787066_EDE2596E) In-Reply-To: References: <20120706125043.GA23189@pandem0nium> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1977207.R232PZQPUF"; micalg="pgp-sha512"; protocol="application/pgp-signature" Sender: linux-wireless-owner@vger.kernel.org List-ID: --nextPart1977207.R232PZQPUF Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On Friday 06 July 2012 19:32:41 Mohammed Shafi wrote: > Hi Simon, > > On Fri, Jul 6, 2012 at 6:20 PM, Simon Wunderlich > > wrote: > > Hey, > > > > we have trouble with an AR9330 (Hornet) based AP. This device has 2 > > antennas, and is supposed to support diversity (2 RX, 1 TX). However, > > diversity is not really enabled because the "alternative" antenna is not > > considered as "good", because not enough frames are received. It seems > > that at 99% of the time, alt_rssi (read from rs->rs_rssi_ctl1) is invalid > > (set to ATH9K_RSSI_BAD, -128), while main_rssi (read from > > rs->rs_rssi_ctl0) usually has sane values. > its been some good amount of time i had taken/tested take a look at > this. actually Gabor Juhos added the support for AR9330. > seems AR9003 family chipsets can exhibit this behaviour. i quickly > checked with AR9285(AR9002) which seems to have a positive RSSI > regulary in ctl0/ctl1. > i also have a AR9485(AR9003 family) which might be similar to AR9330. > just checked with removing the antenna in chain0 seems to bring > positive values in rssi_ctl1. > I just also observer the chain0 is "preferred" unless the RSSI is so > poor in it so chain1 is taken. > Please check if this work out for your case too. Removing the antenna on chain0 doesn't change the alt_rssi value for us. We only noticed that frames with alt_rssi != -128 have the value rx_ant_conf == 1 (LNA2) when only chain1 is attached and rx_ant_conf == 2 (LNA1) when both/chain0-only are attached. Still most of the packets had alt_rssi == -128 and we saw changes in curr_main_set and curr_alt_set (after lot of data was sent). > also please see the throughput difference with/without antenna > diversity with one antenna broken. We (Simon and me) tried to play with the antennas and came to following results: * Both attached: 45 Mibit/s * chain0 attached: 45 Mibit/s * chain1 attached: 15 seconds nearly nothing, after that 25 Mibit/s > I will check out the proper technical reason for such a > preference/compare with AR9285 (or) if its a bug in the code itself. > thanks for looking into this feature! Thanks Kind regards, Sven --nextPart1977207.R232PZQPUF Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAABCgAGBQJP9wCmAAoJEF2HCgfBJntGTwEQAJc4/wxwNRew4cmBHCBFZfqB mpjB9rMwiOmRoalGJZ36PsUMMmgvGWZst9lOMsA135zc7BgufFqdZ2GT59gzFQNx 8DQ/qIX9pihfDAqfmafCxU7g3OO0GlCqi76KC6QGozpqBa7Yf4b8QXE2jBpLyrJS pz+dUCFHEXoHL/0GgE0s9OHGlzpsZTjLbCLCgwxxInNOdcg13G3iMDJ0w3xOPc/Y jwRxjt6/jEBFiP/1/fC+bNnqi4PUUT6wZYhXAGJ7JxmcsDZDBwwiyfwruJfFnAH4 OjoCktZKjXcvOq4Wvi6qb9q7VrHrWd6esG9Cp4wu8q9oyduX54MWWFi/mCVzFV5U Y+MBB3FbuIVFhIDOVEDQJvtVLEcDL4VCEm7MNegI/MHEKAXxi3MZyDI3jNL5VWMU a0xVMdBIhyPUoDZE4ux3+PUg1O7QYcJjuixzNxcAT2o5M7km4XIL6cOGQDijblMv 1lCO2ooY2e3k4A6OzYtAptBqPmF8zCUFcaDcCNM9in1FPdlM3TQ39V6dEHrfwsAj qC4z8etfWR+M06c7UWgT9l7w2L+t0R2Ku8HK5XZlYz52r2HlY7t0g1o2XvU7fNbe u3ekJGWtLiIHIo/NPqN7CkT7vXs6VTFxPAwDBsEh2apvjj8mvKB+a5zWS6JzLkc9 hpWXN08/jwxNUs5ixcQf =pHmo -----END PGP SIGNATURE----- --nextPart1977207.R232PZQPUF--