... and FYI - one of them is wrong - i'll back it out once i figure out why the FreeBSD AP side is being garbage and commit a better "spec compliant" fix.
ugh.. :( -a On 27 November 2016 at 21:29, Peter Wemm <pe...@wemm.org> wrote: > There were two commits in the window where src-committers@ was broken. > > https://svnweb.freebsd.org/changeset/base/309222 > https://svnweb.freebsd.org/changeset/base/309223 > > ------------------------------------------------------------------------ > r309223 | adrian | 2016-11-27 18:59:33 -0800 (Sun, 27 Nov 2016) | 54 lines > Changed paths: > M /head/sys/dev/ath/if_ath_beacon.c > > [ath] fix target beacon interval programming for STA mode when in powersave. > > This bug has been bugging me for quite some time. I finally sat down > with enough coffee to figure it out. > > The short of it - rounding up to the next intval multiple of the TSF value > only works if the AP is transmitting all its beacons on an interval of > the TSF. If it isn't - for example, doing staggered beacons on a multi-VAP > setup with a single hardware TSF - then weird things occur. > > The long of it - > > When powersave is enabled, the MAC and PHY are partially powered off. > They can't receive any packets (or transmit, for that matter.) > The target beacon timer programming will wake up the MAC/PHY just before > the beacon is supposed to be received (well, strictly speaking, at DTIM > so it can see the TIM - traffic information map - telling the STA whether > any traffic is there for it) and it happens automatically. > > However, this relies on the target beacon time being programmed correctly. > If it isn't then the hardware will wake up and not hear any beacons - > and then it'll be asleep for said beacons. After enough of this, net80211 > will give up and assume the AP went away. > > This should fix both TSFOOR interrupts and disconnects from APs with powersave > enabled. > > The annoying bit is that it only happens if APs stagger things or start > on a non-zero TSF. So, this would sometimes be fine and sometimes not be > fine. > > What: > > * I don't know (yet) why the code rounds up to the next intval. > For now, just disable rounding it and trust the value we get. > > TODO: > > * If we do see a beacon miss in STA mode then we should transition > out of sleep for a while so we can hear beacons to resync against. > I'd love a patch from someone to enable that particular behaviour. > Note - that doesn't require that net80211 brings the chip out of > sleep state - only that we wake the chip up through to full-on and > then let it go to sleep again when we've seen a beacon. The wifi > stack and AP can still completely just stay believing we're in sleep > mode. > > Tested: > > * AR9485, STA mode, powersave enabled > > MFC after: 1 week > Relnotes: Yes > > ------------------------------------------------------------------------ > r309222 | adrian | 2016-11-27 18:51:55 -0800 (Sun, 27 Nov 2016) | 5 lines > Changed paths: > M /head/sys/dev/ath/if_ath_rx.c > > [ath] include logging of TU versions of the TSF values. > > The beacon programming side of things deals in TUs and 1/8th TUs, so > it's good to se the TU value here when debugging beaconing issues. > > ------------------------------------------------------------------------ > > > -- > Peter Wemm - pe...@wemm.org; pe...@freebsd.org; pe...@yahoo-inc.com; KI6FJV > UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246 > _______________________________________________ freebsd-wireless@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-wireless To unsubscribe, send any mail to "freebsd-wireless-unsubscr...@freebsd.org"
