linux-kernel - Re: [PATCH 1/1] acer-wmi: switch driver to dev_pm

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Message-Id: <EF5CB084-D774-49E3-9E9F-6803ECB9862C@gmail.com>
Date:	Sun, 26 Jul 2009 14:33:00 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Arnaud Faucher <arnaud.faucher@...il.com>
Cc:	Carlos Corbacho <carlos@...angeworlds.co.uk>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Frans Pop <elendil@...net.nl>,
	Manuel Lauss <manuel.lauss@...il.com>,
	Erik Ekman <erik@...o.se>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Subject: Re: [PATCH 1/1] acer-wmi: switch driver to dev_pm_ops

On Jul 26, 2009, at 1:28 PM, Arnaud Faucher <arnaud.faucher@...il.com>  
wrote:

> On dim, 2009-07-26 at 19:35 +0100, Carlos Corbacho wrote:
>> On Sunday 26 July 2009 19:08:09 Dmitry Torokhov wrote:
>>> On Sun, Jul 26, 2009 at 03:23:29PM +0100, Carlos Corbacho wrote:
>>>> [Removing linux-mips from CC - I don't know why they'd be  
>>>> interested in
>>>> an x86 only platform driver...]
>>>>
>>>> On Sunday 26 July 2009 14:53:33 Arnaud Faucher wrote:
>>>>> Gets rid of the following warning:
>>>>> Platform driver 'acer-wmi' needs updating - please use dev_pm_ops
>>>>>
>>>>> Take 2, thanks to Dmitry, Rafael and Frans for pointing out PM  
>>>>> issue on
>>>>> hibernation when using dev_pm_ops blindly.
>>>>>
>>>>> This patch was tested against suspendand hibernation (Acer mail  
>>>>> led
>>>>> status).
>>>>>
>>>>> Signed-off-by: Arnaud Faucher <arnaud.faucher@...il.com>
>>>>> ---
>>>>> drivers/platform/x86/acer-wmi.c |   17 ++++++++++++-----
>>>>> 1 files changed, 12 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/platform/x86/acer-wmi.c
>>>>> b/drivers/platform/x86/acer-wmi.c
>>>>> index be2fd6f..29374bc 100644
>>>>> --- a/drivers/platform/x86/acer-wmi.c
>>>>> +++ b/drivers/platform/x86/acer-wmi.c
>>>>> @@ -1152,8 +1152,7 @@ static int acer_platform_remove(struct
>>>>> platform_device *device)
>>>>>    return 0;
>>>>> }
>>>>>
>>>>> -static int acer_platform_suspend(struct platform_device *dev,
>>>>> -pm_message_t state)
>>>>> +static int acer_platform_suspend(struct device *dev)
>>>>> {
>>>>>    u32 value;
>>>>>    struct acer_data *data = &interface->data;
>>>>> @@ -1174,7 +1173,7 @@ pm_message_t state)
>>>>>    return 0;
>>>>> }
>>>>>
>>>>> -static int acer_platform_resume(struct platform_device *device)
>>>>> +static int acer_platform_resume(struct device *dev)
>>>>> {
>>>>>    struct acer_data *data = &interface->data;
>>>>>
>>>>> @@ -1190,15 +1189,23 @@ static int acer_platform_resume(struct
>>>>> platform_device *device)
>>>>>    return 0;
>>>>> }
>>>>>
>>>>> +static struct dev_pm_ops acer_platform_pm_ops = {
>>>>> +    .suspend = acer_platform_suspend,
>>>>> +    .resume = acer_platform_resume,
>>>>
>>>> Are these necessary? For suspend-to-RAM, I've never needed these.  
>>>> The old
>>>> callbacks here were just for suspend-to-disk.
>>>
>>> That is not correct. Old suspend and resume callbacks were called  
>>> for
>>> both S2R and S2D. Whether it is actually needed for S2R I don't  
>>> know but
>>> looking at the code they should not hurt.
>>
>> I'm aware they were called for S2RAM as well, but that was just a  
>> limitation
>> of the old calls - as I say, they're not needed for it (at least on  
>> my
>> hardware anyway).
>>
>
> I was looking for similar functionality.
>
>>>>> +    .freeze = acer_platform_suspend,
>>>>> +    .thaw = acer_platform_resume,
>>>>
>>>> If we only need these callbacks for freeze & thaw, they should be
>>>> rebamed.
>>>>
>>>>> +    .poweroff = acer_platform_suspend,
>>>>> +    .restore = acer_platform_resume,
>>>>
>>>> What do poweroff and restore mean in this context. Do my comments  
>>>> above
>>>> apply again (i.e. are the callbacks necessary here)?
>>>
>>> I don't think poweroff handler is needed.
>
> After testing many combinations, I observed that I had to use that  
> much
> callbacks. For example, when omitting to wire .poweroff/.restore,
> with .freeze/.thaw linked to suspend()/resume(), the state (of the  
> mail
> led) is not restored correctly after S2D.


Have you tried with just 3 - freeze, thaw and restore?

>

-- 
Dmitry

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