From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH] cpuidle: coupled: Enable interrupts when early returning on invalid driver Date: Thu, 24 Jul 2014 11:46:31 +0200 Message-ID: <1406195191.21857.6.camel@AMDC1943> References: <1406193999-20300-1-git-send-email-k.kozlowski@samsung.com> <53D0D348.406@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <53D0D348.406@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Daniel Lezcano Cc: "Rafael J. Wysocki" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Colin Cross , Kyungmin Park , Marek Szyprowski , Bartlomiej Zolnierkiewicz , stable@vger.kernel.org List-Id: linux-pm@vger.kernel.org On czw, 2014-07-24 at 11:35 +0200, Daniel Lezcano wrote: > On 07/24/2014 11:26 AM, Krzysztof Kozlowski wrote: > > cpuidle_enter_state is expected to return with interrupts enabled. > > However cpuidle_enter_state_coupled returned with interrupts disabled if > > the cpuidle driver was registered without mask of coupled cpus. > > Hi Krzysztof, > > may be your patch is right but I would like to clarify one thing. This > is the cpuidle driver for exynos. AFAICT, the coupled states shouldn't > be enabled for this driver, so how did you face this issue ? I faced this on cpuidle drivers on both Exynos and MSM. But these were not mainline cpuidle drivers. Best regards, Krzysztof > > This could be observed as a warning: > > [ 1.613132] ------------[ cut here ]------------ > > [ 1.613244] WARNING: CPU: 0 PID: 0 at kernel/sched/idle.c:175 cpu_idle_loop+0x2dc/0x6d0() > > [ 1.620268] Modules linked in: > > [ 1.623311] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.16.0-rc4-00102-g7669ccdbf8af-dirty #81 > > [ 1.623619] dwmmc_exynos 12510000.mshc: 1 slots initialized > > [ 1.624890] logger: created 256K log 'log_main' > > [ 1.625483] logger: created 256K log 'log_events' > > [ 1.626084] logger: created 256K log 'log_radio' > > [ 1.626699] logger: created 256K log 'log_system' > > [ 1.655960] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > > [ 1.663679] [] (show_stack) from [] (dump_stack+0x70/0xbc) > > [ 1.670883] [] (dump_stack) from [] (warn_slowpath_common+0x68/0x8c) > > [ 1.678954] [] (warn_slowpath_common) from [] (warn_slowpath_null+0x1c/0x24) > > [ 1.687720] [] (warn_slowpath_null) from [] (cpu_idle_loop+0x2dc/0x6d0) > > [ 1.696052] [] (cpu_idle_loop) from [] (cpupri_find+0x0/0xd4) > > [ 1.703518] [] (cpupri_find) from [] (processor_id+0x0/0x2c) > > [ 1.710917] ---[ end trace a85327313857296e ]--- > > > > Enable the interrupts also when early returning from > > cpuidle_enter_state_coupled due to invalid coupled configuration. > > > > Signed-off-by: Krzysztof Kozlowski > > Fixes: 4126c0197bc8 ("cpuidle: add support for states that affect multiple cpus") > > Cc: > > --- > > drivers/cpuidle/coupled.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c > > index 73fe2f8d7f96..2b57c267e855 100644 > > --- a/drivers/cpuidle/coupled.c > > +++ b/drivers/cpuidle/coupled.c > > @@ -463,8 +463,10 @@ int cpuidle_enter_state_coupled(struct cpuidle_device *dev, > > struct cpuidle_coupled *coupled = dev->coupled; > > int w; > > > > - if (!coupled) > > + if (!coupled) { > > + local_irq_enable(); > > return -EINVAL; > > + } > > > > while (coupled->prevent) { > > cpuidle_coupled_clear_pokes(dev->cpu); > > > >