linux-kernel - Re: Query: When will drv->poweroff() called

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Date:	Thu, 16 Feb 2012 07:16:11 -0800
From:	viresh kumar <viresh.linux@...il.com>
To:	amit.kucheria@...aro.org,
	"linux-pm@...ts.linux-foundation.org" 
	<linux-pm@...ts.linux-foundation.org>
Cc:	Viresh Kumar <viresh.kumar@...com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	"len.brown@...el.com" <len.brown@...el.com>,
	Vipul Kumar SAMAR <vipulkumar.samar@...com>,
	Bhupesh SHARMA <bhupesh.sharma@...com>,
	Pratyush ANAND <pratyush.anand@...com>,
	Armando VISCONTI <armando.visconti@...com>,
	Mirko GARDI <mirko.gardi@...com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Vipin KUMAR <vipin.kumar@...com>,
	Shiraz HASHIM <shiraz.hashim@...com>,
	Amit VIRDI <Amit.VIRDI@...com>,
	Rajeev KUMAR <rajeev-dlh.kumar@...com>,
	"pavel@....cz" <pavel@....cz>, Deepak SIKRI <deepak.sikri@...com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Vincenzo FRASCINO <Vincenzo.FRASCINO@...com>
Subject: Re: Query: When will drv->poweroff() called

[Sorry for mailing again, earlier mail bounced on linux-pm list,
as i wasn't subscribed to it]

Hi Amit,

Can you please clear my doubt regarding calling of
hibernation_set_ops() for ARM SoC's?

--
viresh

On Mon, Feb 6, 2012 at 8:19 PM, Viresh Kumar <viresh.kumar@...com> wrote:
> On 2/6/2012 5:37 PM, Rafael J. Wysocki wrote:
>> On Monday, February 06, 2012, Viresh Kumar wrote:
>>> >
>>> > Hi Guys,
>>> >
>>> > Sorry for asking this silly question, but i couldn't locate much
>>> > help for it in documentation, so asking it.
>>> >
>>> > We were testing hibernation for SPEAr13xx SoC family, based on
>>> > ARM Cortex a9.
>>> >
>>> > I observed that poweroff() callback of individual drivers are not
>>> > getting called at all, while we test hibernate.
>> They should be called in the last phase of hibernation, after the image
>> has been created and the system is going for "power off" (hance the
>> callback name).
>>
>>> > I tried to go through the code to see what happened. It looked like
>>> > there should be call to hibernation_set_ops() for platforms that are
>>> > willing to get a call to poweroff() for their drivers.
>> That's correct.  The ->poweroff() callbacks are only executed if
>> hibernation_mode is equal to HIBERNATION_PLATFORM, which is not the
>> default.
>>
>>> > Otherwise shutdown of the busses gets called, which is a completely
>>> > different path.
>>> >
>>> > There are many drivers today, that are registering poweroff() from dev_pm_ops
>>> > but are not doing bus specific shutdown stuff.
>>> >
>>> > Even i tried to look for hibernation_set_ops() in kernel, and only acpi
>>> > code is calling it.
>> That's correct too.
>>
>>> > I didn't understood how other ARM Sub-Arch's are handling this.
>> Well, they are supposed to call hibernation_set_ops() and set the operations
>> appropriately.  Those operations may be empty routines if they don't need
>> to do anything, but they have to be defined.
>
> Hi Amit,
>
> Can you give some input on why none of the ARM platforms are calling
> this routine currently.
--
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