On Tue, Sep 14, 2010 at 1:06 PM, Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx> wrote: > On Tue, Sep 14, 2010 at 10:56:14AM -0700, Luis R. Rodriguez wrote: >> On Tue, Sep 14, 2010 at 9:42 AM, Luis R. Rodriguez >> <lrodriguez@xxxxxxxxxxx> wrote: >> > On Tue, Sep 14, 2010 at 9:39 AM, Luis R. Rodriguez >> > <lrodriguez@xxxxxxxxxxx> wrote: >> >> On Tue, Sep 14, 2010 at 8:00 AM, Luis R. Rodriguez >> >> <lrodriguez@xxxxxxxxxxx> wrote: >> >>> When we return to the home channel we were never reseting our beacon >> >>> timers, this was casued by the fact that the scanning flag was still >> >>> on even after we returned to our home channel. There are also other >> >>> reasons why we would get a reset and if we are not off channel >> >>> we always need to resynch our beacon timers, because a reset will >> >>> clear them. >> >>> >> >>> For more details refer to: >> >>> >> >>> http://code.google.com/p/chromium-os/issues/detail?id=5715 >> >>> >> >>> This bug is a regression introduced on 2.6.36. The order of the >> >>> changes are as follows: >> >>> >> >>> 5ee08656 - Sat Jul 31 - ath9k: prevent calibration during off-channel activity >> >>> a0daa0e7 - Tue Jul 27 - Revert "mac80211: fix sw scan bracketing" >> >>> 543708be - Fri Jun 18 - mac80211: fix sw scan bracketing >> >>> >> >>> mcgrof@tux ~/linux-2.6-allstable (git::master)$ git describe \ >> >>> --contains 5ee0865615f65f84e6ee9174771a6716c29e08e1 >> >>> v2.6.36-rc1~43^2~34^2~22 >> >>> >> >>> mcgrof@tux ~/linux-2.6-allstable (git::master)$ git describe \ >> >>> --contains a0daa0e7592ada797d6835f11529097aabc27ad2 >> >>> v2.6.36-rc1~571^2~64^2~13 >> >>> >> >>> mcgrof@tux ~/linux-2.6-allstable (git::master)$ git describe \ >> >>> --contains 543708be320d7df692d24b349ca01a947b340764 >> >>> v2.6.36-rc1~571^2~107^2~187 >> >>> >> >>> So 5ee08656 would have worked if a0daa0e7 was not committed but >> >>> it was so this means 5ee08656 was broken since it assumed that >> >>> when we were in the channel change routine the scan flag would >> >>> be lifted. As it turns out the scan flag will be set when we >> >>> are already on the home channel. >> >>> >> >>> These issues will need to be considered for our solution on >> >>> reshifting the scan complete callback location on mac80211 on >> >>> current development kernel work. >> >>> >> >>> This patch has stable fixes which apply down to [2.6.36+] >> >>> >> >>> Cc: stable@xxxxxxxxxx >> >>> Cc: Paul Stewart <pstew@xxxxxxxxxx> >> >>> Cc: Amod Bodas <amod.bodas@xxxxxxxxxxx> >> >>> Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx> >> >>> --- >> >>> >> >>> This v2 clarifies the second to last sentence, on the v1 this >> >>> was just jiberish on my first read.. this should clarify what >> >>> I meant. >> >>> >> >>> drivers/net/wireless/ath/ath9k/main.c | 6 ++++-- >> >>> 1 files changed, 4 insertions(+), 2 deletions(-) >> >>> >> >>> diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c >> >>> index ba029b2..e349619 100644 >> >>> --- a/drivers/net/wireless/ath/ath9k/main.c >> >>> +++ b/drivers/net/wireless/ath/ath9k/main.c >> >>> @@ -258,9 +258,11 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, >> >>> if (!(sc->sc_flags & (SC_OP_OFFCHANNEL | SC_OP_SCANNING))) { >> >>> ath_start_ani(common); >> >>> ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work, 0); >> >>> - ath_beacon_config(sc, NULL); >> >>> } >> >>> >> >>> + if (!(sc->sc_flags & (SC_OP_OFFCHANNEL))) >> >>> + ath_beacon_config(sc, NULL); >> >>> + >> >> >> >> Upon further thought this change should just remove the SC_OP_SCANNING >> >> flag from above and let the code there run when we are not off >> >> channel. Reason is that as I noted above on the commit log entry the >> >> scan flag will be set even when we return to the home channel due to >> >> the races in mac80211 that were actually fixed by Johannes but later >> >> reverted due to issues. Doing the fix this way would also let us >> >> re-arm ANI and the tx completion monitor, this was also broken! I'll >> >> respin this patch shortly after some basic testing. >> > >> > I should also note that this patch fixes the issue of reseting the >> > beacon timers upon a reset, likely when the tx monitor hits -- I >> > suspect that when that currently would hit we'd actually be out of >> > synch with the AP and disconnect. This patch fixes that, but I just >> > reviewed older kernels and the offchannel flag was not available prior >> > to 2.6.36 so we can only fix this properly on >= 2.6.36 unless we >> > figure out a way to annotate we're on the home channel. If we do we >> > can potentially propagate a fix down to older kernels than 2.6.36 >> > eventually. >> >> Fun, just noticed these would be busted too :) >> >> ath9k_hw_startpcureceive(ah, (sc->sc_flags & SC_OP_SCANNING)); >> >> Ah, joy. > > More joy, so I tried this as an alternative: > > diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h > index 5fe570b..ecd6724 100644 > --- a/drivers/net/wireless/ath/ath9k/ath9k.h > +++ b/drivers/net/wireless/ath/ath9k/ath9k.h > @@ -563,7 +563,6 @@ struct ath_ant_comb { > #define SC_OP_RXFLUSH BIT(7) > #define SC_OP_LED_ASSOCIATED BIT(8) > #define SC_OP_LED_ON BIT(9) > -#define SC_OP_SCANNING BIT(10) > #define SC_OP_TSF_RESET BIT(11) > #define SC_OP_BT_PRIORITY_DETECTED BIT(12) > #define SC_OP_BT_SCAN BIT(13) > diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c > index ba029b2..2207cf2 100644 > --- a/drivers/net/wireless/ath/ath9k/main.c > +++ b/drivers/net/wireless/ath/ath9k/main.c > @@ -255,7 +255,7 @@ int ath_set_channel(struct ath_softc *sc, struct ieee80211_hw *hw, > ath_update_txpow(sc); > ath9k_hw_set_interrupts(ah, ah->imask); > > - if (!(sc->sc_flags & (SC_OP_OFFCHANNEL | SC_OP_SCANNING))) { > + if (!(sc->sc_flags & SC_OP_OFFCHANNEL)) { > ath_start_ani(common); > ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work, 0); > ath_beacon_config(sc, NULL); > @@ -957,7 +957,7 @@ int ath_reset(struct ath_softc *sc, bool retry_tx) > > ath_update_txpow(sc); > > - if (sc->sc_flags & SC_OP_BEACONS) > + if ((sc->sc_flags & SC_OP_BEACONS) || !(sc->sc_flags & (SC_OP_OFFCHANNEL))) > ath_beacon_config(sc, NULL); /* restart beacons */ > > ath9k_hw_set_interrupts(ah, ah->imask); > @@ -2042,7 +2042,6 @@ static void ath9k_sw_scan_start(struct ieee80211_hw *hw) > > aphy->state = ATH_WIPHY_SCAN; > ath9k_wiphy_pause_all_forced(sc, aphy); > - sc->sc_flags |= SC_OP_SCANNING; > mutex_unlock(&sc->mutex); > } > > @@ -2057,7 +2056,6 @@ static void ath9k_sw_scan_complete(struct ieee80211_hw *hw) > > mutex_lock(&sc->mutex); > aphy->state = ATH_WIPHY_ACTIVE; > - sc->sc_flags &= ~SC_OP_SCANNING; > mutex_unlock(&sc->mutex); > } > > diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c > index 87e02f5..6f7d4d1 100644 > --- a/drivers/net/wireless/ath/ath9k/recv.c > +++ b/drivers/net/wireless/ath/ath9k/recv.c > @@ -301,7 +301,7 @@ static void ath_edma_start_recv(struct ath_softc *sc) > > ath_opmode_init(sc); > > - ath9k_hw_startpcureceive(sc->sc_ah, (sc->sc_flags & SC_OP_SCANNING)); > + ath9k_hw_startpcureceive(sc->sc_ah, !!(sc->sc_flags & SC_OP_OFFCHANNEL)); > } > > static void ath_edma_stop_recv(struct ath_softc *sc) > @@ -507,7 +507,7 @@ int ath_startrecv(struct ath_softc *sc) > start_recv: > spin_unlock_bh(&sc->rx.rxbuflock); > ath_opmode_init(sc); > - ath9k_hw_startpcureceive(ah, (sc->sc_flags & SC_OP_SCANNING)); > + ath9k_hw_startpcureceive(ah, !!(sc->sc_flags & SC_OP_OFFCHANNEL)); > > return 0; > } > > > But the harware goes nutty. Although technically it seems correct I manged to figure out the issue, ANI needs to be started *after* the beacon config. I'm going to split up these two fixes up separatey though as one fixes the beacon loss as a regression, the other fixes a long time issue of having left ANI completely disabled when doing a bg scan. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
