From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from he.sipsolutions.net ([78.46.109.217]:60114 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753273Ab2DAVLz (ORCPT ); Sun, 1 Apr 2012 17:11:55 -0400 Message-ID: <1333314713.22977.2.camel@jlt3.sipsolutions.net> (sfid-20120401_231158_569360_B30B6A44) Subject: Re: [RFC] mac80211: Support on-channel scan option. From: Johannes Berg To: Ben Greear Cc: linux-wireless@vger.kernel.org Date: Sun, 01 Apr 2012 23:11:53 +0200 In-Reply-To: <4F78C056.4080307@candelatech.com> References: <1333233041-3246-1-git-send-email-greearb@candelatech.com> (sfid-20120401_003057_469452_61057064) <1333305916.3703.2.camel@jlt3.sipsolutions.net> <4F78BE67.8090609@candelatech.com> <1333313357.22977.0.camel@jlt3.sipsolutions.net> <4F78C056.4080307@candelatech.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Sun, 2012-04-01 at 13:53 -0700, Ben Greear wrote: > On 04/01/2012 01:49 PM, Johannes Berg wrote: > > On Sun, 2012-04-01 at 13:45 -0700, Ben Greear wrote: > >> On 04/01/2012 11:45 AM, Johannes Berg wrote: > >>> On Sat, 2012-03-31 at 15:30 -0700, greearb@candelatech.com wrote: > >>> > >>> > >>>> static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, > >>>> struct cfg80211_scan_request *req) > >>>> @@ -438,6 +461,33 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, > >>>> local->scan_req = req; > >>>> local->scan_sdata = sdata; > >>>> > >>>> + /* If we are scanning only on the current channel, then > >>>> + * we do not need to stop normal activities > >>>> + */ > >>>> + if ((req->n_channels == 1)&& > >>>> + (req->channels[0]->center_freq == > >>>> + local->hw.conf.channel->center_freq)) { > >>> ... > >>>> + return 0; > >>>> + } > >>>> + > >>>> if (local->ops->hw_scan) > >>>> __set_bit(SCAN_HW_SCANNING,&local->scanning); > >>> > >>> Clearly, you're joking. > >> > >> That is worthless feedback and gives me no idea what you > >> think should be fixed about it. > >> > >> If you hate the entire idea of optimizing scanning on channel, > >> just say so plainly. > > > > I did quote only the relevant pieces -- you're completely ignoring hw > > scan. Why should I care about this patch then? > > Well, I was hoping that a simple scan-on-channel wouldn't need to > care about the hw-scan logic. So you thought about it, but didn't document it? This bothers me quite a bit -- why should I have to always do the thinking again? > But, I can change it so that the optimized scan-on-channel only > is supported on NICs that do software-scan? In any case, yes, you'll have to do that. Think about how scanning works, and consider that devices may very well chose to filter by BSSID when associated etc. johannes