Return-path: Received: from mga14.intel.com ([143.182.124.37]:5642 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753771Ab2DROvR (ORCPT ); Wed, 18 Apr 2012 10:51:17 -0400 Date: Wed, 18 Apr 2012 17:52:04 +0300 From: Andrei Emeltchenko To: Johannes Berg Cc: Marcel Holtmann , linux-bluetooth@vger.kernel.org, linux-wireless@vger.kernel.org Subject: Re: [RFCv1] mac80211: Adds Software / Virtual AMP 80211 Message-ID: <20120418145202.GH19228@aemeltch-MOBL1> (sfid-20120418_165126_416732_CF03747C) References: <1334059909-20513-1-git-send-email-Andrei.Emeltchenko.news@gmail.com> <1334059909-20513-2-git-send-email-Andrei.Emeltchenko.news@gmail.com> <4F846257.1060807@sipsolutions.net> <1334092668.16897.54.camel@aeonflux> <4F84A422.3030900@sipsolutions.net> <4F84A52A.7050905@sipsolutions.net> <20120411071119.GC17779@aemeltch-MOBL1> <1334714611.3725.34.camel@jlt3.sipsolutions.net> <20120418121551.GE19228@aemeltch-MOBL1> <4F8ED1D0.1070401@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <4F8ED1D0.1070401@sipsolutions.net> Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi Johannes, On Wed, Apr 18, 2012 at 07:38:08AM -0700, Johannes Berg wrote: > On 4/18/2012 5:15 AM, Andrei Emeltchenko wrote: > >>It's never in your best interest to run one supplicant per virtual > >>interface, you want to run one per piece of hardware so it can > >>coordinate between virtual interfaces. > > > >Do I understand it right that virtual interfaces are like separate devices from > >user point of view? If I create virtual interface and assign MAC I can > >transfer data through it without affecting other interfaces? Then > >wpa_supplicant does not need to know about it at all. > > No, this is incorrect. If one device wants to connect on one > channel, the other typically has to use the same channel. If one > device wants to scan, the other will be affected. Some hardware may > support switching around between two channels, but might also > support more than 2 virtual interfaces, so again they won't be > independent. BTW: which devices can switch channels? > Therefore, you need something managing all this concurrency. This is > in a small part the driver which will enforce restrictions (it will > reject new impossible things), but mostly the supplicant which can > make policy decisions about which usage should win. This doesn't sound like a rocket science to me. IMO this might be done in drivers. Those drivers which can switch channels why do they need wpa_supplicant involved making this decision? Best regards Andrei Emeltchenko