linux-kernel - Re: [PATCH] ACPI: evaluate

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Message-ID: <CAF1ivSbOhUbE6wreRQ5E3jV5N_haHn1y9q48CU_OZFeCRTed+A@mail.gmail.com>
Date:	Tue, 24 Apr 2012 21:15:37 +0800
From:	Lin Ming <ming.m.lin@...el.com>
To:	Aaron Lu <aaron.lu@....com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, Len Brown <lenb@...nel.org>,
	linux-acpi@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Zhang Rui <rui.zhang@...el.com>,
	Andiry Xu <andiry.xu@....com>, Alex He <alex.he@....com>
Subject: Re: [PATCH] ACPI: evaluate _PS3 when entering D3 Cold

On Tue, Apr 24, 2012 at 11:10 AM, Aaron Lu <aaron.lu@....com> wrote:
> On Tue, Apr 24, 2012 at 10:29:36AM +0800, Lin Ming wrote:
>> On Tue, 2012-04-24 at 10:07 +0800, Aaron Lu wrote:
>> > On Mon, Apr 23, 2012 at 09:50:57PM +0200, Rafael J. Wysocki wrote:
>> > > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>> > > > index 3263b68..187433f 100644
>> > > > --- a/drivers/acpi/bus.c
>> > > > +++ b/drivers/acpi/bus.c
>> > > > @@ -273,6 +273,9 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
>> > > >                 }
>> > > >         } else {
>> > > >                 if (device->power.states[state].flags.explicit_set) {
>> > > > +                       /* evaluate _PS3 instead of _PS4 when entering D3Cold */
>> > > > +                       if (state == ACPI_STATE_D3)
>> > > > +                               object_name[3] -= 1;
>> > >
>> > > Can you just put '3' here directly?  That'll be much cleaner than the
>> > > subtraction (that could have been -- as well).
>> > >
>> > > >                         status = acpi_evaluate_object(device->handle,
>> > > >                                                       object_name, NULL, NULL);
>> > > >                         if (ACPI_FAILURE(status)) {
>> > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> > > > index 7417267..de2ae10 100644
>> > > > --- a/drivers/acpi/scan.c
>> > > > +++ b/drivers/acpi/scan.c
>> > > > @@ -887,8 +887,12 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
>> > > >                 /* Evaluate "_PSx" to see if we can do explicit sets */
>> > > >                 object_name[2] = 'S';
>> > > >                 status = acpi_get_handle(device->handle, object_name, &handle);
>> > > > -               if (ACPI_SUCCESS(status))
>> > > > +               if (ACPI_SUCCESS(status)) {
>> > > >                         ps->flags.explicit_set = 1;
>> > > > +                       /* Also set D3Cold's explicit flag when _PS3 exists */
>> > > > +                       if (i == ACPI_STATE_D3_HOT)
>> > > > +                               (ps+1)->flags.explicit_set = 1;
>> > >
>> > > Please don't use pointer arithmetics here.  I know it _happens_ to work,
>> > > but I don't think it's appropriate in this situation at all.
>> > >
>> >
>> > Thanks for the suggestions.
>> >
>> > What about this?
>> >
>> > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>> > index 3263b68..3a7860f 100644
>> > --- a/drivers/acpi/bus.c
>> > +++ b/drivers/acpi/bus.c
>> > @@ -273,6 +273,9 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
>> >             }
>> >     } else {
>> >             if (device->power.states[state].flags.explicit_set) {
>> > +                   /* Evaluate _PS3 when entering D3cold */
>> > +                   if (state == ACPI_STATE_D3)
>> > +                           object_name[3] = '3';
>> >                     status = acpi_evaluate_object(device->handle,
>> >                                                   object_name, NULL, NULL);
>> >                     if (ACPI_FAILURE(status)) {
>> > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
>> > index 7417267..734d946 100644
>> > --- a/drivers/acpi/scan.c
>> > +++ b/drivers/acpi/scan.c
>> > @@ -908,6 +908,10 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
>> >     device->power.states[ACPI_STATE_D3].flags.valid = 1;
>> >     device->power.states[ACPI_STATE_D3].power = 0;
>> >
>> > +   /* Also set D3cold's explicit flag when _PS3 exists */
>> > +   if (device->power.states[ACPI_STATE_D3_HOT].flags.explicit_set)
>> > +           device->power.states[ACPI_STATE_D3].flags.explicit_set = 1;
>>
>> We should use ACPI_STATE_D3_COLD instead of ACPI_STATE_D3 to make thing
>> clear.
>>
> Thanks for your suggestion.
>
> Well, considering all those ACPI_STATE_D3 used in tree, I don't think I
> should use ACPI_STATE_D3_COLD here, especially the two lines above are
> still using ACPI_STATE_D3.
>
> But if that is desired, we should probably change all the existing
> ACPI_STATE_D3 macros to ACPI_STATE_D3_COLD to make things clear.
>
> Or we all use ACPI_STATE_D3, since it is defined as 4 and means D3 cold,
> and people will learn this, won't they?
>
> What do you think?

OK.

But we may do more cleanup later.

>
> Thanks,
> Aaron
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