From owner-freebsd-wireless@FreeBSD.ORG Tue Nov 12 13:26:29 2013 Return-Path: Delivered-To: freebsd-wireless@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5FE24D8D for ; Tue, 12 Nov 2013 13:26:29 +0000 (UTC) Received: from mail-ve0-x229.google.com (mail-ve0-x229.google.com [IPv6:2607:f8b0:400c:c01::229]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 2449E2BD3 for ; Tue, 12 Nov 2013 13:26:29 +0000 (UTC) Received: by mail-ve0-f169.google.com with SMTP id pa12so1746601veb.14 for ; Tue, 12 Nov 2013 05:26:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=Ie3FBtkaP7UNNjhflE2yIVyDtAEdeqiiNZn9GKafW8c=; b=VL6KviR0OTCq5rla3Cs45qFhBu/0Cs9ygm0MFAqxgWxkEQXD3LpwFT6r8vZ6f1wsX/ 2dse4DuD/wyqbM+UPJHwmZ3K7VgGS7WV6lM5zd/QXoudkr2W0cRPYnGQ9DLD+x12aSwF sH7rLB4DQ2F8b0U8mGzNdW7Ozuz93uGzL/0/OftZE8gvjzPiGXNx5amO++FCmxeYZGW4 794cAXLX30Gag3XF6QlX/6rkOmr9pZi0hHEAZZ30oDFzKF7MOvBlN5YtsOaHCAOjgRQh jVV/alLZP+3PncR+WSaEzpDVEEWsf8b12jJb0waF8TKr7mrjqTBRWw4w9wsfxdC1fhyR mHGw== X-Received: by 10.220.244.132 with SMTP id lq4mr1475657vcb.31.1384262788211; Tue, 12 Nov 2013 05:26:28 -0800 (PST) MIME-Version: 1.0 Received: by 10.52.228.35 with HTTP; Tue, 12 Nov 2013 05:26:08 -0800 (PST) In-Reply-To: <52821DFC.60203@gmail.com> References: <52821DFC.60203@gmail.com> From: Sergey Ryazanov Date: Tue, 12 Nov 2013 17:26:08 +0400 Message-ID: Subject: Re: [ath5k-devel] Atheros AR5xxx DSSS-OFDM mode support To: Nick Kossifidis Content-Type: text/plain; charset=ISO-8859-1 Cc: ath5k-devel@lists.ath5k.org, freebsd-wireless@freebsd.org X-BeenThere: freebsd-wireless@freebsd.org X-Mailman-Version: 2.1.16 Precedence: list List-Id: "Discussions of 802.11 stack, tools device driver development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Nov 2013 13:26:29 -0000 2013/11/12 Nick Kossifidis : > On Tue 12 Nov 2013 11:55:43 AM GMT, Sergey Ryazanov wrote: >> Hi list, >> >> we test pretty old hardware based on AR5414 chip with pretty old >> madwifi driver, which even use binary hal. Our spectral analyzer shows >> that in 2.4GHz band this chip transmits OFDM-preamble with any of the >> OFDM rates (6-54 mbps), instead of .11b-compatable DSSS-preamble. Does >> anybody could provide some clue: is this chip supports DSSS-OFDM mode >> according to section 19.7 of IEEE 802.11-2012? >> >> When I digging the ath5k code I faced the AR_PHY_MODE (0xa200) >> register, which seems to controls the behavior of chip. This register >> contains two interesting bit: >> AR_PHY_MODE_MOD_CCK bit 0 (0x00000001) >> AR_PHY_MODE_MOD_DYN bit 3 (0x00000004) >> >> If I am correctly understand, _MOD_DYN just enables the CCK (DSSS) >> block. But what the purpose of the AR_PHY_MODE_MOD_CCK bit? >> > > From what I know: > MOD_DYN = CCK + OFDM (for g) > MOD_CCK = CCK only (for b) > Thank you Nick, for your quick answer, may be you know, why we need such explicit option (I mean MOD_CCK bit)? If we would like to act as pure dot11b node, then we could simply limit rate set to DSSS/CCK rates only. Did you know something about DSSS-OFDM mode support in the AR5xxx chips, is it possible at all? -- BR, Sergey