Return-path: Received: from s3.sipsolutions.net ([144.76.43.152]:41963 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbaAPJbw (ORCPT ); Thu, 16 Jan 2014 04:31:52 -0500 Message-ID: <1389864706.4345.1.camel@jlt4.sipsolutions.net> (sfid-20140116_103156_898120_58D2D232) Subject: Re: [RFC 9/9] mac80211: implement multi-interface CSA From: Johannes Berg To: Michal Kazior Cc: linux-wireless Date: Thu, 16 Jan 2014 10:31:46 +0100 In-Reply-To: (sfid-20140116_102805_794169_3235EA94) References: <1389787494-7361-1-git-send-email-michal.kazior@tieto.com> <1389787494-7361-10-git-send-email-michal.kazior@tieto.com> <1389792139.4338.6.camel@jlt4.sipsolutions.net> (sfid-20140116_102805_794169_3235EA94) Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2014-01-16 at 10:28 +0100, Michal Kazior wrote: > On 15 January 2014 14:22, Johannes Berg wrote: > > On Wed, 2014-01-15 at 13:04 +0100, Michal Kazior wrote: > >> This implements a fairly simple multi-interface > >> CSA. It doesn't support multiple channel > >> contexts so it doesn't support multi-channel. > > > > It seems that this also means that somewhere you need to advertise the > > multi-switch feature. I guess you need that anyway, but this makes it > > obvious. > > I don't really understand. Do we really need it? You want to advertise > it just to cfg80211 or all the way up to userspace? It seems it would be needed all the way to userspace so it knows whether it can expect multi-vif CSA to be available? Or would you just want to try & fail? Wouldn't that potentially impact channel selection since you'd want to not pick radar channels for multi-vif? Not really sure ... Maybe the expectation is that internally there will be no drivers that don't support it, i.e. if a driver implements the cfg80211 API at all then it must support multi-vif CSA? johannes