From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Lezcano Subject: Re: [PATCH] cpuidle: coupled: Enable interrupts when early returning on invalid driver Date: Thu, 24 Jul 2014 12:27:28 +0200 Message-ID: <53D0DF90.3040307@linaro.org> References: <1406193999-20300-1-git-send-email-k.kozlowski@samsung.com> <53D0D348.406@linaro.org> <1406195191.21857.6.camel@AMDC1943> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1406195191.21857.6.camel@AMDC1943> Sender: stable-owner@vger.kernel.org To: Krzysztof Kozlowski 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 07/24/2014 11:46 AM, Krzysztof Kozlowski wrote: > 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 disabl= ed 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. Th= is >> 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 wer= e > not mainline cpuidle drivers. Ok, I think the root problem is the FLAG_COUPLED is set for the state=20 but without the cpumask. I don't think we should handle that in the=20 enter_couple function but in the registering of the device and fail to=20 register the driver/device if the informations are not properly set. In this case, we know the sanity checks are done one time at the=20 registering time and we don't need to do that each time when entering i= n=20 the enter coupled function. Hence the "if (!coupled)" disappear and no=20 need to re-enable the irq. >>> This could be observed as a warning: >>> [ 1.613132] ------------[ cut here ]------------ >>> [ 1.613244] WARNING: CPU: 0 PID: 0 at kernel/sched/idle.c:175 cp= u_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 [] (s= how_stack+0x10/0x14) >>> [ 1.663679] [] (show_stack) from [] (dump_st= ack+0x70/0xbc) >>> [ 1.670883] [] (dump_stack) from [] (warn_sl= owpath_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 [] (cpup= ri_find+0x0/0xd4) >>> [ 1.703518] [] (cpupri_find) from [] (proces= sor_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 m= ultiple 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 =3D dev->coupled; >>> int w; >>> >>> - if (!coupled) >>> + if (!coupled) { >>> + local_irq_enable(); >>> return -EINVAL; >>> + } >>> >>> while (coupled->prevent) { >>> cpuidle_coupled_clear_pokes(dev->cpu); >>> >> >> > --=20 Linaro.org =E2=94=82 Open source software fo= r ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog