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ath9k: fix interrupt storms on queued hardware reset 

commit b74713d04e
"ath9k: Handle fatal interrupts properly" introduced a race condition, where
IRQs are being left enabled, however the irq handler returns IRQ_HANDLED
while the reset is still queued without addressing the IRQ cause.
This leads to an IRQ storm that prevents the system from even getting to
the reset code.

Fix this by disabling IRQs in the handler without touching intr_ref_cnt.

Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Cc: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Felix Fietkau 2012-08-08 16:25:03 +02:00 committed by John W. Linville
parent bbf2e65258
commit f41a9b3b15
3 changed files with 16 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/net/wireless/ath/ath9k/mac.c
View File

@ -773,15 +773,10 @@ bool ath9k_hw_intrpend(struct ath_hw *ah)
}
EXPORT_SYMBOL(ath9k_hw_intrpend);
void ath9k_hw_disable_interrupts(struct ath_hw *ah)
void ath9k_hw_kill_interrupts(struct ath_hw *ah)
{
struct ath_common *common = ath9k_hw_common(ah);
if (!(ah->imask & ATH9K_INT_GLOBAL))
atomic_set(&ah->intr_ref_cnt, -1);
else
atomic_dec(&ah->intr_ref_cnt);
ath_dbg(common, INTERRUPT, "disable IER\n");
REG_WRITE(ah, AR_IER, AR_IER_DISABLE);
(void) REG_READ(ah, AR_IER);
@ -793,6 +788,17 @@ void ath9k_hw_disable_interrupts(struct ath_hw *ah)
(void) REG_READ(ah, AR_INTR_SYNC_ENABLE);
}
}
EXPORT_SYMBOL(ath9k_hw_kill_interrupts);
void ath9k_hw_disable_interrupts(struct ath_hw *ah)
{
if (!(ah->imask & ATH9K_INT_GLOBAL))
atomic_set(&ah->intr_ref_cnt, -1);
else
atomic_dec(&ah->intr_ref_cnt);
ath9k_hw_kill_interrupts(ah);
}
EXPORT_SYMBOL(ath9k_hw_disable_interrupts);
void ath9k_hw_enable_interrupts(struct ath_hw *ah)

1
drivers/net/wireless/ath/ath9k/mac.h
View File

@ -738,6 +738,7 @@ bool ath9k_hw_intrpend(struct ath_hw *ah);
void ath9k_hw_set_interrupts(struct ath_hw *ah);
void ath9k_hw_enable_interrupts(struct ath_hw *ah);
void ath9k_hw_disable_interrupts(struct ath_hw *ah);
void ath9k_hw_kill_interrupts(struct ath_hw *ah);
void ar9002_hw_attach_mac_ops(struct ath_hw *ah);

4
drivers/net/wireless/ath/ath9k/main.c
View File

@ -462,8 +462,10 @@ irqreturn_t ath_isr(int irq, void *dev)
if (!ath9k_hw_intrpend(ah))
return IRQ_NONE;
if(test_bit(SC_OP_HW_RESET, &sc->sc_flags))
if (test_bit(SC_OP_HW_RESET, &sc->sc_flags)) {
ath9k_hw_kill_interrupts(ah);
return IRQ_HANDLED;
}
/*
* Figure out the reason(s) for the interrupt. Note