Return-path: Received: from mga14.intel.com ([143.182.124.37]:45051 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751363AbZG3RpX (ORCPT ); Thu, 30 Jul 2009 13:45:23 -0400 Subject: Re: [PATCH] mac80211: use beacons for connection monitoring From: reinette chatre To: Johannes Berg Cc: Ben Greear , "linville@tuxdriver.com" , "linux-wireless@vger.kernel.org" In-Reply-To: <1248949853.29062.3.camel@johannes.local> References: <1248903159-17024-1-git-send-email-reinette.chatre@intel.com> <4A70C17B.6090309@candelatech.com> <1248949853.29062.3.camel@johannes.local> Content-Type: text/plain Date: Thu, 30 Jul 2009 10:45:23 -0700 Message-Id: <1248975923.1216.1074.camel@rc-desk> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2009-07-30 at 03:30 -0700, Johannes Berg wrote: > On Wed, 2009-07-29 at 14:39 -0700, Ben Greear wrote: > > On 07/29/2009 02:32 PM, Reinette Chatre wrote: > > > From: Reinette Chatre > > > > > > The connection monitor currently relies on probe requests paired > > > with probe responses to ensure that a connection is alive. This is > > > fragile in some environments where probe responses can get lost. > > > When we receive beacons we can also consider the connection to be > > > alive, so cancel connection poll instance when we receive a beacon. > > > > I'm chasing a similar problem while working on virtual STA device > > support in ath5k. I was also going to try sending up to 3 polls before > > giving up on the connection. Does that seems like a valid thing to do? > > That seems somewhat better, yeah. > > I suspect the real cause of the issue is something else though, like the > probe request not going out properly or the card being in a kind of > 'temporary lock-up' state where it's not really doing anything for the > time being -- I've never had a problem on any other (than iwlwifi) > hardware. I captured the exchange when this problem occurs using a third system. The card does indeed try several times to send a probe request and they are making it out over the air. The AP never responds. Is there perhaps anything in this exchange that can help us understand what is going on? No. Time Source Destination Protocol Info 163883 401.891153 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=980, FN=0, Flags=........, SSID="XXX" 163885 401.891482 00:14:f2:XX:XX:XX 00:16:ea:XX:XX:XX IEEE 802.11 Probe Response, SN=3557, FN=0, Flags=........, BI=100, SSID="XXX" 165523 404.884405 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=981, FN=0, Flags=........, SSID="XXX" 165525 404.885265 00:14:f2:XX:XX:XX 00:16:ea:XX:XX:XX IEEE 802.11 Probe Response, SN=3827, FN=0, Flags=....R..., BI=100, SSID="XXX" 166981 407.884161 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=982, FN=0, Flags=........, SSID="XXX" 166983 407.884555 00:14:f2:XX:XX:XX 00:16:ea:XX:XX:XX IEEE 802.11 Probe Response, SN=4034, FN=0, Flags=........, BI=100, SSID="XXX" 168133 410.884167 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=........, SSID="XXX" 168134 410.884430 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168135 410.884643 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168136 410.884904 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168137 410.885073 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168138 410.885330 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168139 410.885580 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168140 410.885769 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168141 410.886618 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168142 410.887087 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168143 410.887308 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168144 410.887532 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Probe Request, SN=983, FN=0, Flags=....R..., SSID="XXX" 168191 411.084889 00:16:ea:XX:XX:XX 00:14:f2:XX:XX:XX IEEE 802.11 Deauthentication, SN=984, FN=0, Flags=........ Reinette