The patch titled
cpuidle: always return with interrupts enabled
has been removed from the -mm tree. Its filename was
cpuidle-always-return-with-interrupts-enabled.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cpuidle: always return with interrupts enabled
From: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
In the case where cpuidle_idle_call() returns before changing state due to
a need_resched(), it was returning with IRQs disabled.
The idle path assumes that the platform specific idle code returns with
interrupts enabled (although this too is undocumented AFAICT) and on ARM
we have a WARN_ON(!(irqs_disabled()) when returning from the idle loop, so
the user-visible effects were only a warning since interrupts were
eventually re-enabled later.
On x86, this same problem exists, but there is no WARN_ON() to detect it.
As on ARM, the interrupts are eventually re-enabled, so I'm not sure of
any actual bugs triggered by this. It's primarily a
correctness/consistency fix.
This patch ensures IRQs are (re)enabled before returning.
Reported-by: Hemanth V <hemanthv@xxxxxx>
Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Cc: Len Brown <len.brown@xxxxxxxxx>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxx>
Tested-by: Martin Michlmayr <tbm@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx> [2.6.31.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN drivers/cpuidle/cpuidle.c~cpuidle-always-return-with-interrupts-enabled drivers/cpuidle/cpuidle.c
--- a/drivers/cpuidle/cpuidle.c~cpuidle-always-return-with-interrupts-enabled
+++ a/drivers/cpuidle/cpuidle.c
@@ -76,8 +76,11 @@ static void cpuidle_idle_call(void)
#endif
/* ask the governor for the next state */
next_state = cpuidle_curr_governor->select(dev);
- if (need_resched())
+ if (need_resched()) {
+ local_irq_enable();
return;
+ }
+
target_state = &dev->states[next_state];
/* enter the state and update stats */
_
Patches currently in -mm which might be from khilman@xxxxxxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
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