Return-path: Received: from mail-iw0-f174.google.com ([209.85.214.174]:44689 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754369Ab1A2Afh (ORCPT ); Fri, 28 Jan 2011 19:35:37 -0500 Received: by iwn9 with SMTP id 9so3637223iwn.19 for ; Fri, 28 Jan 2011 16:35:36 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <4D435D76.2040703@candelatech.com> References: <4D4345A8.6060806@candelatech.com> <4D435D76.2040703@candelatech.com> From: Daniel Halperin Date: Fri, 28 Jan 2011 16:35:16 -0800 Message-ID: Subject: Re: hti->control_chan is 15?? To: Ben Greear Cc: linux-wireless@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, Jan 28, 2011 at 4:21 PM, Ben Greear wrote: > On 01/28/2011 02:39 PM, Ben Greear wrote: >> >> When testing with 60 stations, 30 against a netgear running HT40 >> and 30 against a cheap cisco AP, using HT20, I notice that the >> stations on the netgear often choose NO_HT instead of HT40 >> for their channel type. >> >> The root cause appears to be that the hti->control_chan is 15 >> in the ieee80211_enable_ht method. >> >> Everything *should* be running on channel 11. >> >> Is this just a bug with the AP, or could this be a local >> issue? > > I sniffed on a separate machine (using ath9k NIC), and it agrees > that the beacon's control_channel is 14 (I have since set the AP to channel > 10 instead of 11, but the control_channel remains 4 higher than expected.) > How did you configure the AP to HT40 mode? Did you put HT40+ or HT40- in the hostapd.conf file? Look at IEEE 802.11n-2009, Annex I and J. They explain what these mean and which combinations are valid in which sets. Looks like you're using a weird domain and/or disabled ath's regulatory checks? I'd think that they would catch this otherwise. Or, it could also be a bug related to the Japan regulatory stuff that seemed to cause problems for iwlwifi also. Dan