From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wi0-f181.google.com ([209.85.212.181]:61356 "EHLO mail-wi0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752843AbaEWJLz convert rfc822-to-8bit (ORCPT ); Fri, 23 May 2014 05:11:55 -0400 Received: by mail-wi0-f181.google.com with SMTP id n15so511339wiw.14 for ; Fri, 23 May 2014 02:11:53 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1400835214.4358.8.camel@jlt4.sipsolutions.net> References: <1400767676-15994-1-git-send-email-michal.kazior@tieto.com> <1400767676-15994-7-git-send-email-michal.kazior@tieto.com> <1400770624.4174.36.camel@jlt4.sipsolutions.net> <1400835214.4358.8.camel@jlt4.sipsolutions.net> Date: Fri, 23 May 2014 11:11:53 +0200 Message-ID: (sfid-20140523_111207_578682_464E0C96) Subject: Re: [PATCH v6 6/6] cfg80211: remove channel_switch combination check From: Michal Kazior To: Johannes Berg Cc: linux-wireless , Luca Coelho Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 23 May 2014 10:53, Johannes Berg wrote: > On Fri, 2014-05-23 at 09:04 +0200, Michal Kazior wrote: >> On 22 May 2014 16:57, Johannes Berg wrote: >> > On Thu, 2014-05-22 at 16:07 +0200, Michal Kazior wrote: >> >> Make the driver responsible for making sure it is >> >> capable of performing the switch. It might as well >> >> accept a request but then disconnect an interface >> >> if some requirements are not met. >> > >> > Care to elaborate? I'd really like to avoid this case as much as >> > possible, so just mentioning here that it would be valid seems like a >> > bad idea. >> >> Well, CSA isn't really visible to cfg80211 so you can't enforce anything now. >> >> Also since CSA requests are submitted one-by-one you already break >> interface combinations and hope: >> a) userspace sends more CSA requests soon enough to make future >> interface combination valid >> b) trust drivers deal with it either way >> >> So why bother? >> >> The most you can probably do is to prevent CSA requests from switching >> to too many different channels but you can easily guarantee this in a >> driver. > > Yeah, absolutely - it's just the fact that you're saying that it might > accept but then disconnect ... that will make people feel OK about that, > when it's really not all that desirable. Better to state that more > explicitly that it should check before :) I understand now. I'll try to emphasize this when I respin. Michał