Return-path: Received: from mail-pa0-f43.google.com ([209.85.220.43]:63539 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752240AbaKYLKp (ORCPT ); Tue, 25 Nov 2014 06:10:45 -0500 Received: by mail-pa0-f43.google.com with SMTP id kx10so396842pab.2 for ; Tue, 25 Nov 2014 03:10:44 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1416913453.2045.4.camel@sipsolutions.net> References: <1416911009-22405-1-git-send-email-johannes@sipsolutions.net> <1416913453.2045.4.camel@sipsolutions.net> Date: Tue, 25 Nov 2014 19:10:44 +0800 Message-ID: (sfid-20141125_121049_444506_F480B745) Subject: Re: [PATCH] mac80211: check if channels allow 80 MHz for VHT probe requests From: YanBo To: Johannes Berg Cc: linux-wireless Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Nov 25, 2014 at 7:04 PM, Johannes Berg wrote: > On Tue, 2014-11-25 at 19:00 +0800, YanBo wrote: >> On Tue, Nov 25, 2014 at 6:23 PM, Johannes Berg >> wrote: >> > From: Johannes Berg >> > >> > If there are no channels allowing 80 MHz to be used, then the >> > station isn't really VHT capable even if the driver and device >> > support it in general. In this case, exclude the VHT capability >> > IE from probe request frames. >> > >> >> FYI, there are some new devices could support the VHT even at 20Mhz >> band 2.4G mode. > > So in 2.4 GHz we typically don't have VHT anyway - and realistically you > can't support real "VHT" there, you can only support the new > modulations. I think this will require some custom (vendor-specific) > advertisement though, since VHT advertisement implies 80 MHz support. > > IOW, I think at this point this patch isn't a problem. If we really need > to support VHT modulations in 2.4 GHz (or even have devices that have > VHT modulation support, but no 80 MHz support in 5 GHz) then some new > advertisement will have to be done. > We already start the working to support the VHT modulations MCS8 and MCS9 support in 2.4G for ath10k devices, and it used the band->vht_cap = vht_cap to notification the mac80211, if we band it with 80MHz, it is do need another new advertisement for this as your said. Thanks BR /Yanbo