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

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Message-Id: <201204231343.03382.rjw@sisk.pl>
Date:	Mon, 23 Apr 2012 13:43:03 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Aaron Lu <aaron.lu@....com>
Cc:	Len Brown <lenb@...nel.org>, Lin Ming <ming.m.lin@...el.com>,
	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 Monday, April 23, 2012, Aaron Lu wrote:
> Hi Rafael and Ming,
> 
> Do you have any more comments on this patch?
> If not, can I have your ack? Thanks.
> 
> -Aaron
> 
> On Sun, Apr 01, 2012 at 02:18:30AM +0800, Aaron Lu wrote:
> > When entering D3 Cold from a higher device state, evaluate _PS3 first
> > and then make the proper power transition.
> > This is used to solve the ZPODD problem on AMD's platform, _PS3 on such
> > platforms will power off the ODD device and thus make the device enter
> > D3 cold state.
> > 
> > Signed-off-by: Aaron Lu <aaron.lu@....com>
> > Cc: Andiry Xu <andiry.xu@....com>
> > Cc: Alex He <alex.he@....com>
> > ---
> >  drivers/acpi/bus.c |   17 ++++++++++++++---
> >  1 file changed, 14 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> > index 3263b68..68e593f 100644
> > --- a/drivers/acpi/bus.c
> > +++ b/drivers/acpi/bus.c
> > @@ -227,6 +227,8 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
> >  	int result = 0;
> >  	acpi_status status = AE_OK;
> >  	char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
> > +	struct acpi_device_power_state *ps;
> > +	u8 explicit_set;
> >  
> >  	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
> >  		return -EINVAL;
> > @@ -239,7 +241,8 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
> >  		return 0;
> >  	}
> >  
> > -	if (!device->power.states[state].flags.valid) {
> > +	ps = &device->power.states[state];
> > +	if (!ps->flags.valid) {
> >  		printk(KERN_WARNING PREFIX "Device does not support D%d\n", state);
> >  		return -ENODEV;
> >  	}
> > @@ -263,7 +266,7 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
> >  			if (result)
> >  				goto end;
> >  		}
> > -		if (device->power.states[state].flags.explicit_set) {
> > +		if (ps->flags.explicit_set) {
> >  			status = acpi_evaluate_object(device->handle,
> >  						      object_name, NULL, NULL);
> >  			if (ACPI_FAILURE(status)) {
> > @@ -272,7 +275,15 @@ static int __acpi_bus_set_power(struct acpi_device *device, int state)
> >  			}
> >  		}
> >  	} else {
> > -		if (device->power.states[state].flags.explicit_set) {
> > +		/* If state is D3 Cold, try to evaluate _PS3 first */
> > +		if (state == ACPI_STATE_D3_COLD) {
> > +			explicit_set = (ps - 1)->flags.explicit_set;
> > +			object_name[3] -= 1;
> > +		}
> > +		else {
> > +			explicit_set = ps->flags.explicit_set;
> > +		}

I really don't like this.  I think you should modify acpi_bus_get_power_flags(),
on top of the recent Lin Ming's patch, so that it sets flags.explicit_set for
D3_COLD if _PS3 is present and _PR3 is not.

I'm not sure you'll need the $subject patch any more then.

> > +		if (explicit_set) {
> >  			status = acpi_evaluate_object(device->handle,
> >  						      object_name, NULL, NULL);
> >  			if (ACPI_FAILURE(status)) {

Thanks,
Rafael
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