ath9k has a race on putting the chip into network sleep and having registers read from hardware. The race occurs because although ath9k_ps_restore() locks its own callers it makes use of some variables which get altered in the driver at different code paths. The variables are the ps_enabled and ps_flags. This is easily reprodicible in large network environments when roaming with the wpa_supplicant simple bgscan. You'd get some 0xdeadbeef read out on certain registers such as: ath: timeout (100000 us) on reg 0x806c: 0xdeadbeef & 0x01f00000 != 0x00000000 ath: RX failed to go idle in 10 ms RXSM=0xdeadbeef ath: timeout (100000 us) on reg 0x7000: 0xdeadbeef & 0x00000003 != 0x00000000 ath: Chip reset failed The fix is to protect the ath9k_config(hw, IEEE80211_CONF_CHANGE_PS) calls with a spin_lock_irqsave() which will disable contendors for these variables from interrupt context, timers, re-entry from mac80211 on the same callback, and most importantly from ath9k_ps_restore() which is the only call which will put the device into network sleep. There are quite a few threads and bug reports on these a few of them are: https://bugs.launchpad.net/ubuntu/karmic/+source/linux/+bug/407040 http://code.google.com/p/chromium-os/issues/detail?id=5709 http://code.google.com/p/chromium-os/issues/detail?id=5943 Stable fixes apply to [2.6.32+] Cc: stable@xxxxxxxxxx Cc: Paul Stewart <pstew@xxxxxxxxxx> Cc: Amod Bodas <amod.bodas@xxxxxxxxxxx> Signed-off-by: Luis R. Rodriguez <lrodriguez@xxxxxxxxxxx> --- drivers/net/wireless/ath/ath9k/main.c | 5 ++++- drivers/net/wireless/ath/ath9k/recv.c | 3 +++ 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index a2f7eb2..826315d 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -1554,6 +1554,8 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) * IEEE80211_CONF_CHANGE_PS is only passed by mac80211 for STA mode. */ if (changed & IEEE80211_CONF_CHANGE_PS) { + unsigned long flags; + spin_lock_irqsave(&sc->sc_pm_lock, flags); if (conf->flags & IEEE80211_CONF_PS) { sc->ps_flags |= PS_ENABLED; /* @@ -1568,7 +1570,7 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) sc->ps_enabled = false; sc->ps_flags &= ~(PS_ENABLED | PS_NULLFUNC_COMPLETED); - ath9k_setpower(sc, ATH9K_PM_AWAKE); + ath9k_hw_setpower(sc->sc_ah, ATH9K_PM_AWAKE); if (!(ah->caps.hw_caps & ATH9K_HW_CAP_AUTOSLEEP)) { ath9k_hw_setrxabort(sc->sc_ah, 0); @@ -1583,6 +1585,7 @@ static int ath9k_config(struct ieee80211_hw *hw, u32 changed) } } } + spin_unlock_irqrestore(&sc->sc_pm_lock, flags); } if (changed & IEEE80211_CONF_CHANGE_MONITOR) { diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c index 6fb3b45..7523f7d 100644 --- a/drivers/net/wireless/ath/ath9k/recv.c +++ b/drivers/net/wireless/ath/ath9k/recv.c @@ -1640,6 +1640,7 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp) u8 rx_status_len = ah->caps.rx_status_len; u64 tsf = 0; u32 tsf_lower = 0; + unsigned long flags; if (edma) dma_type = DMA_BIDIRECTIONAL; @@ -1748,11 +1749,13 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp) sc->rx.rxotherant = 0; } + spin_lock_irqsave(&sc->sc_pm_lock, flags); if (unlikely(ath9k_check_auto_sleep(sc) || (sc->ps_flags & (PS_WAIT_FOR_BEACON | PS_WAIT_FOR_CAB | PS_WAIT_FOR_PSPOLL_DATA)))) ath_rx_ps(sc, skb); + spin_unlock_irqrestore(&sc->sc_pm_lock, flags); if (ah->caps.hw_caps & ATH9K_HW_CAP_ANT_DIV_COMB) ath_ant_comb_scan(sc, &rs); -- 1.7.0.4 -- 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
