Return-path: Received: from ebb06.tieto.com ([131.207.168.38]:48098 "EHLO ebb06.tieto.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752185Ab2JWGUS (ORCPT ); Tue, 23 Oct 2012 02:20:18 -0400 Message-ID: <5086371D.2080108@tieto.com> (sfid-20121023_082022_834528_AE0F1A66) Date: Tue, 23 Oct 2012 08:20:13 +0200 From: Michal Kazior MIME-Version: 1.0 To: Victor Goldenshtein CC: "linux-wireless@vger.kernel.org" , "kgiori@qca.qualcomm.com" , "mcgrof@frijolero.org" , "zefir.kurtisi@neratec.com" , "adrian.chadd@gmail.com" , "j@w1.fi" , "johannes@sipsolutions.net" , "coelho@ti.com" , "assaf@ti.com" , "igalc@ti.com" , "adrian@freebsd.org" , "nbd@nbd.name" , "simon.wunderlich@s2003.tu-chemnitz.de" Subject: Re: [PATCH v4 5/6] nl80211/cfg80211: add ap channel switch command References: <1350226137-13704-1-git-send-email-victorg@ti.com> <1350226137-13704-6-git-send-email-victorg@ti.com> In-Reply-To: <1350226137-13704-6-git-send-email-victorg@ti.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: On 14/10/12 16:48, Victor Goldenshtein wrote: > +static int nl80211_ap_channel_switch(struct sk_buff *skb, > + struct genl_info *info) > +{ This function should probably enforce interface combinations with `cfg80211_can_use_chan()`. Otherwise we might end up in a state which doesn't correspond to any interface combination - and won't be able to bring up new interfaces. This however introduces a new problem. Let's suppose we have 2 APs on channel 1. The device doesn't support multi-channel. We won't be able to switch channel on these APs at all. We might want to change the channel switch to resolve around the channel itself (not the interface) - so we'd be saying "move all interfaces with channel X to channel Y" instead of "move interface X to channel Y". Or we could let the driver decide what it'll do - e.g. silently switch more than one interface to a different channel (which makes sense with AP/DFS I guess) and just notify cfg/userspace about it. That would require us to provide a way to switch interfaces (atomically possibly) between channels while keeping in sync with interface combinations though. We might try addressing station CSA issue at the same time maybe? -- Pozdrawiam / Best regards, Michal Kazior.