Return-path: Received: from mail-bk0-f54.google.com ([209.85.214.54]:58083 "EHLO mail-bk0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359AbaAWMl1 convert rfc822-to-8bit (ORCPT ); Thu, 23 Jan 2014 07:41:27 -0500 Received: by mail-bk0-f54.google.com with SMTP id u14so334905bkz.27 for ; Thu, 23 Jan 2014 04:41:26 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1390478961.4142.12.camel@jlt4.sipsolutions.net> References: <1390227670-19030-1-git-send-email-michal.kazior@tieto.com> <1390227670-19030-6-git-send-email-michal.kazior@tieto.com> <1390316761.6199.27.camel@jlt4.sipsolutions.net> <1390380726.4334.4.camel@jlt4.sipsolutions.net> <1390382020.4334.17.camel@jlt4.sipsolutions.net> <1390385995.4334.27.camel@jlt4.sipsolutions.net> <1390394166.4189.28.camel@porter.coelho.fi> <1390403432.4334.33.camel@jlt4.sipsolutions.net> <1390403634.4189.39.camel@porter.coelho.fi> <1390458664.4189.48.camel@porter.coelho.fi> <1390462306.4189.56.camel@porter.coelho.fi> <1390478961.4142.12.camel@jlt4.sipsolutions.net> Date: Thu, 23 Jan 2014 13:41:26 +0100 Message-ID: (sfid-20140123_134131_670314_101F8549) Subject: Re: [PATCH 5/7] mac80211: improve CSA locking From: Michal Kazior To: Johannes Berg Cc: Luca Coelho , linux-wireless , "Otcheretianski, Andrei" Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 23 January 2014 13:09, Johannes Berg wrote: > On Thu, 2014-01-23 at 08:57 +0100, Michal Kazior wrote: > >> This is actually the tricky part. How do you automatically switch an >> AP interface? You should be able to at least generate CSA IE - true - >> but what about beacon after CSA? You need to update HT IE and VHT IE >> at least. >> >> Perhaps we could split CSA into two parts somehow and make it more >> userspace coordinated. The first part of CSA - announcing it, is >> trivial and can actually be done entirely within mac80211 if I'm not >> mistaken. What needs userspace input is what happens after the >> announcement. This would mean that there is a possible time gap >> between announcement being completed and the actual channel switch & >> operation resuming. > > I believe that even announcing it isn't necessarily possible without > userspace involvement, particularly for things like 11ac's channel > switch wrapper IE and/or operating class changes. Aww, too bad then. But splitting would still be useful (at least in some sense) if you consider CSA to "usable" DFS channels. Michał