Date: Tue, 01 Jul 2008 15:54:05 -0700 From: Sam Leffler <sam@errno.com> To: Sepherosa Ziehau <sepherosa@gmail.com> Cc: freebsd-net <freebsd-net@freebsd.org>, Andrew Thompson <thompsa@freebsd.org>, Joseph Lee <nugundam@nugundam.best.vwh.net> Subject: Re: kern/124753: net80211 discards power-save queue packets early Message-ID: <486AB58D.7050005@errno.com> In-Reply-To: <ea7b9c170806190622u5a9501a4vab53ff1be8c9368a@mail.gmail.com> References: <200806191030.m5JAU36i027140@freefall.freebsd.org> <ea7b9c170806190622u5a9501a4vab53ff1be8c9368a@mail.gmail.com>
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Sepherosa Ziehau wrote: > On Thu, Jun 19, 2008 at 6:30 PM, <remko@freebsd.org> wrote: > >> Synopsis: net80211 discards power-save queue packets early >> >> Responsible-Changed-From-To: freebsd-i386->freebsd-net >> Responsible-Changed-By: remko >> Responsible-Changed-When: Thu Jun 19 10:29:47 UTC 2008 >> Responsible-Changed-Why: >> reassign to networking team. >> >> http://www.freebsd.org/cgi/query-pr.cgi?pr=124753 >> > > In How-To-Repeat, you said: > "Then associate a recent Windows Mobile 6.1 device to the FreeBSD box > running hostapd ..." > > In Description, you said: > "The WM6.1 device recv ps-poll's for packets every 20 seconds ..." > > AFAIK, STA sends ps-poll to AP; AP does not send ps-poll to STA. Why > did your windows STA receive ps-poll from freebsd AP? Did you capture > it by using 802.11 tap? > > And which freebsd driver were you using? > > Your problem looks like: > - Either freebsd AP did not properly configure TIM in beacons, which > could be easily found out by using 802.11 tap. But I highly suspect > if you were using ath(4), TIM would be misconfigured. > - Or your windows STA didn't process TIM according to 802.11 standard. > > The PR states the listen interval sent by the station is 3 (beacons) and the beacon interval is 100TU. This means the AP is required to buffer unicast frames for only 300TU which is ~300 ms. But according to the report the Windows device is polling every 20 seconds so there's no guarantee any packets will be present (even with the net80211 code arbitrarily using 4x the list interval specified by the sta). I find it really hard to believe a device would poll every 20 secs so something seems wrong in what's reported/observed. Given that defeating the aging logic just pushed the problem elsewhere it sounds like there's something else wrong which (as you note) probably requires a packet capture to understand. I'm pretty sure TIM is handled correctly in RELENG_7 but a packet capture would help us verify that. Sam
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