Author: adrian
Date: Sat Apr 23 06:37:09 2011
New Revision: 220966
URL: http://svn.freebsd.org/changeset/base/220966
Log:
Fix a corner-case of interrupt handling which resulted in potentially
spurious (and fatal) interrupt errors.
One user reported seeing this:
Apr 22 18:04:24 ceres kernel: ar5416GetPendingInterrupts: fatal error,
ISR_RAC 0x0 SYNC_CAUSE 0x2000
SYNC_CAUSE of 0x2000 is AR_INTR_SYNC_LOCAL_TIMEOUT which is a bus timeout;
this shouldn't cause HAL_INT_FATAL to be set.
After checking out ath9k, ath9k_ar9002_hw_get_isr() clears (*masked)
before continuing, regardless of whether any bits in the ISR registers
are set. So if AR_INTR_SYNC_CAUSE is set to something that isn't
treated as fatal, and AR_ISR isn't read or is read and is 0, then
(*masked) wouldn't be cleared. Thus any of the existing bits set
that were passed in would be preserved in the output.
The caller in if_ath - ath_intr() - wasn't setting the masked value
to 0 before calling ath_hal_getisr(), so anything that was present
in that uninitialised variable would be preserved in the case above
of AR_ISR=0, AR_INTR_SYNC_CAUSE != 0; and if the HAL_INT_FATAL bit
was set, a fatal condition would be interpreted and the chip was
reset.
This patch does the following:
* ath_intr() - set masked to 0 before calling ath_hal_getisr();
* ar5416GetPendingInterrupts() - clear (*masked) before processing
continues; so if the interrupt source is AR_INTR_SYNC_CAUSE
and it isn't fatal, the hardware isn't reset via returning
HAL_INT_FATAL.
This doesn't fix any underlying errors which trigger
AR_INTR_SYNC_LOCAL_TIMEOUT - which is a bus timeout of some
sort - so that likely should be further investigated.
Modified:
head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c
head/sys/dev/ath/if_ath.c
Modified: head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c
==============================================================================
--- head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c Sat Apr 23 05:56:06
2011 (r220965)
+++ head/sys/dev/ath/ath_hal/ar5416/ar5416_interrupts.c Sat Apr 23 06:37:09
2011 (r220966)
@@ -55,6 +55,8 @@ ar5416IsInterruptPending(struct ath_hal
* values. The value returned is mapped to abstract the hw-specific bit
* locations in the Interrupt Status Register.
*
+ * (*masked) is cleared on initial call.
+ *
* Returns: A hardware-abstracted bitmap of all non-masked-out
* interrupts pending, as well as an unmasked value
*/
@@ -73,10 +75,10 @@ ar5416GetPendingInterrupts(struct ath_ha
isr = 0;
sync_cause = OS_REG_READ(ah, AR_INTR_SYNC_CAUSE);
sync_cause &= AR_INTR_SYNC_DEFAULT;
- if (isr == 0 && sync_cause == 0) {
- *masked = 0;
+ *masked = 0;
+
+ if (isr == 0 && sync_cause == 0)
return AH_FALSE;
- }
if (isr != 0) {
struct ath_hal_5212 *ahp = AH5212(ah);
Modified: head/sys/dev/ath/if_ath.c
==============================================================================
--- head/sys/dev/ath/if_ath.c Sat Apr 23 05:56:06 2011 (r220965)
+++ head/sys/dev/ath/if_ath.c Sat Apr 23 06:37:09 2011 (r220966)
@@ -1265,7 +1265,7 @@ ath_intr(void *arg)
struct ath_softc *sc = arg;
struct ifnet *ifp = sc->sc_ifp;
struct ath_hal *ah = sc->sc_ah;
- HAL_INT status;
+ HAL_INT status = 0;
if (sc->sc_invalid) {
/*
@@ -1296,6 +1296,11 @@ ath_intr(void *arg)
ath_hal_getisr(ah, &status); /* NB: clears ISR too */
DPRINTF(sc, ATH_DEBUG_INTR, "%s: status 0x%x\n", __func__, status);
status &= sc->sc_imask; /* discard unasked for bits */
+
+ /* Short-circuit un-handled interrupts */
+ if (status == 0x0)
+ return;
+
if (status & HAL_INT_FATAL) {
sc->sc_stats.ast_hardware++;
ath_hal_intrset(ah, 0); /* disable intr's until reset */
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