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authorKevin Hilman <khilman@deeprootsystems.com>2009-10-26 16:50:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-29 07:39:31 -0700
commit246eb7f0ed1a8aeddec5313137767658f378949b (patch)
tree25cfbdab4d133ebb1539b3c8b4e302f1ca7866b3
parent5e8d8f6f2844d4a663415c660ab5cc92e2e2477d (diff)
cpuidle: always return with interrupts enabled
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@ti.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Len Brown <len.brown@intel.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Tested-by: Martin Michlmayr <tbm@cyrius.com> Cc: <stable@kernel.org> [2.6.31.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/cpuidle/cpuidle.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index ad41f19b8e3..12fdd3987a3 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/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 */