linux-kernel - Re: [PATCH v2] leds: fix hibernation on arm when gpio-led used with CPU led trigger

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Date:	Wed, 18 Mar 2015 21:39:13 +0200
From:	"Grygorii.Strashko@...aro.org" <grygorii.strashko@...aro.org>
To:	Bryan Wu <cooloney@...il.com>, Richard Purdie <rpurdie@...ys.net>,
	linux-leds@...r.kernel.org
CC:	sumit.semwal@...aro.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	"Menon, Nishanth" <nm@...com>, Kevin Hilman <khilman@...aro.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH v2] leds: fix hibernation on arm when gpio-led used with
 CPU led trigger

Hi All,

On 02/24/2015 06:12 PM, Grygorii.Strashko@...aro.org wrote:
> On 02/05/2015 04:37 PM, grygorii.strashko@...aro.org wrote:
>> From: Grygorii Strashko <Grygorii.Strashko@...aro.org>
>>
>> Setting a dev_pm_ops suspend/resume pair of callbacks but not a set of
>> hibernation callbacks means those pm functions will not be
>> called upon hibernation - that leads to system crash on ARM during
>> freezing if gpio-led is used in combination with CPU led trigger.
>> It may happen after freeze_noirq stage (GPIO is suspended)
>> and before syscore_suspend stage (CPU led trigger is suspended)
>> - usually when disable_nonboot_cpus() is called.
>>
>> Log:
>>     PM: noirq freeze of devices complete after 1.425 msecs
>>     Disabling non-boot CPUs ...
>>       ^ system may crash or stuck here with message (TI AM572x)
>>
>>     WARNING: CPU: 0 PID: 3100 at drivers/bus/omap_l3_noc.c:148 l3_interrupt_handler+0x22c/0x370()
>>     44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4_PER1_P3 (Idle): Data Access in Supervisor mode during Functional access
>>
>>     CPU1: shutdown
>>       ^ or here
>>
>> Fix this by using SIMPLE_DEV_PM_OPS, which appropriately
>> assigns the suspend and hibernation callbacks and move
>> led_suspend/led_resume under CONFIG_PM_SLEEP to avoid
>> build warnings.
>>
>> Signed-off-by: Grygorii Strashko <Grygorii.Strashko@...aro.org>
>> ---
>> This patch actually fixes commit:
>>    73e1ab4 "leds: Convert led class driver from legacy pm ops to dev_pm_ops"
>>
On 02/24/2015 06:12 PM, Grygorii.Strashko@...aro.org wrote:
>> Changes in v2:
>> - fixed compile time warnings when !CONFIG_PM_SLEEP
>> - updated commit message
>>
>> v1:
>> - https://lkml.org/lkml/2015/2/2/476
>>
>>    drivers/leds/led-class.c | 7 +++----
>>    1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
>> index dbeebac..5033e0d 100644
>> --- a/drivers/leds/led-class.c
>> +++ b/drivers/leds/led-class.c
>> @@ -183,6 +183,7 @@ void led_classdev_resume(struct led_classdev *led_cdev)
>>    }
>>    EXPORT_SYMBOL_GPL(led_classdev_resume);
>>
>> +#ifdef CONFIG_PM_SLEEP
>>    static int led_suspend(struct device *dev)
>>    {
>>    	struct led_classdev *led_cdev = dev_get_drvdata(dev);
>> @@ -202,11 +203,9 @@ static int led_resume(struct device *dev)
>>
>>    	return 0;
>>    }
>> +#endif
>>
>> -static const struct dev_pm_ops leds_class_dev_pm_ops = {
>> -	.suspend        = led_suspend,
>> -	.resume         = led_resume,
>> -};
>> +static SIMPLE_DEV_PM_OPS(leds_class_dev_pm_ops, led_suspend, led_resume);
>>
>>    /**
>>     * led_classdev_register - register a new object of led_classdev class.
>>
>
> Could you pay attention on this patch, pls? It fixes a real issue for me.
>
> Actually, I'd like to note that it fixes regression introduced by commit
> 73e1ab41a80d36207e8ea7cc2c9897afdeeef387
> "leds: Convert led class driver from legacy pm ops to dev_pm_ops" from
> Shuah Khan <shuah.kh@...sung.com> (Jun 20 2013).
>

Gentle reminder. Any comments on this?

-- 
regards,
-grygorii
--
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