From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prashant Gaikwad Subject: Re: [PATCH 1/3] cpuidle: coupled: disable interrupts after entering safe state Date: Thu, 29 Aug 2013 12:20:14 +0530 Message-ID: <521EEF26.80803@nvidia.com> References: <1377287112-12018-1-git-send-email-ccross@android.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1377287112-12018-1-git-send-email-ccross@android.com> Sender: stable-owner@vger.kernel.org To: Colin Cross Cc: "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Neil Zhang , Joseph Lo , "linux-tegra@vger.kernel.org" , "stable@vger.kernel.org" , "Rafael J. Wysocki" , Daniel Lezcano List-Id: linux-pm@vger.kernel.org On Saturday 24 August 2013 01:15 AM, Colin Cross wrote: > Calling cpuidle_enter_state is expected to return with interrupts > enabled, but interrupts must be disabled before starting the > ready loop synchronization stage. Call local_irq_disable after > each call to cpuidle_enter_state for the safe state. > > CC: stable@vger.kernel.org > Signed-off-by: Colin Cross > --- > drivers/cpuidle/coupled.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c > index 2a297f8..db92bcb 100644 > --- a/drivers/cpuidle/coupled.c > +++ b/drivers/cpuidle/coupled.c > @@ -460,6 +460,7 @@ int cpuidle_enter_state_coupled(struct cpuidle_device *dev, > } > entered_state = cpuidle_enter_state(dev, drv, > dev->safe_state_index); > + local_irq_disable(); Colin, There is still some window where irq remains enabled after exiting safe state. It may introduce some corner case. Instead of this can we pass a parameter to cpuidle_enter_state indicating that irq has to be enabled or not after exit from idle state, which would be false when entering safe state from coupled idle. > } > > /* Read barrier ensures online_count is read after prevent is cleared */ > @@ -485,6 +486,7 @@ retry: > > entered_state = cpuidle_enter_state(dev, drv, > dev->safe_state_index); > + local_irq_disable(); > } > > if (cpuidle_coupled_clear_pokes(dev->cpu)) {