linux-kernel - Re: [PATCH 5/7] ACPI / PM: Provide device PM functions operating on struct acpi

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Date:	Tue, 30 Oct 2012 16:20:10 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Aaron Lu <aaron.lu@...el.com>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Huang Ying <ying.huang@...el.com>,
	LKML <linux-kernel@...r.kernel.org>, Len Brown <lenb@...nel.org>,
	Lv Zheng <lv.zheng@...el.com>,
	Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH 5/7] ACPI / PM: Provide device PM functions operating on struct acpi_device

On Tuesday, October 30, 2012 03:28:45 PM Aaron Lu wrote:
> On Mon, Oct 29, 2012 at 10:11:20AM +0100, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > 
> > If the caller of acpi_bus_set_power() already has a pointer to the
> > struct acpi_device object corresponding to the device in question, it
> > doesn't make sense for it to go through acpi_bus_get_device(), which
> > may be costly, because it involves acquiring the global ACPI
> > namespace mutex.
> > 
> > For this reason, export the function operating on struct acpi_device
> > objects used internally by acpi_bus_set_power(), so that it may be
> > called instead of acpi_bus_set_power() in the above case, and change
> > its name to acpi_device_set_power().
> > 
> > Additionally, introduce two inline wrappers for checking ACPI PM
> > capabilities of devices represented by struct acpi_device objects.
> 
> What about adding yet another wrapper to check power off capability of
> the device? If device has _PS3 or _PRx, it means the device can be
> powered off from ACPI's perspective. This is useful for ZPODD when
> deciding if platform has the required ability to support it.

Sure, no problem with that.  Perhaps you can cut a patch for that
on top of this series?

Rafael


> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >  drivers/acpi/bus.c      |   15 ++++++++++++---
> >  include/acpi/acpi_bus.h |   11 +++++++++++
> >  2 files changed, 23 insertions(+), 3 deletions(-)
> > 
> > Index: linux/drivers/acpi/bus.c
> > ===================================================================
> > --- linux.orig/drivers/acpi/bus.c
> > +++ linux/drivers/acpi/bus.c
> > @@ -257,7 +257,15 @@ static int __acpi_bus_get_power(struct a
> >  }
> >  
> >  
> > -static int __acpi_bus_set_power(struct acpi_device *device, int state)
> > +/**
> > + * acpi_device_set_power - Set power state of an ACPI device.
> > + * @device: Device to set the power state of.
> > + * @state: New power state to set.
> > + *
> > + * Callers must ensure that the device is power manageable before using this
> > + * function.
> > + */
> > +int acpi_device_set_power(struct acpi_device *device, int state)
> >  {
> >  	int result = 0;
> >  	acpi_status status = AE_OK;
> > @@ -341,6 +349,7 @@ static int __acpi_bus_set_power(struct a
> >  
> >  	return result;
> >  }
> > +EXPORT_SYMBOL(acpi_device_set_power);
> >  
> >  
> >  int acpi_bus_set_power(acpi_handle handle, int state)
> > @@ -359,7 +368,7 @@ int acpi_bus_set_power(acpi_handle handl
> >  		return -ENODEV;
> >  	}
> >  
> > -	return __acpi_bus_set_power(device, state);
> > +	return acpi_device_set_power(device, state);
> >  }
> >  EXPORT_SYMBOL(acpi_bus_set_power);
> >  
> > @@ -402,7 +411,7 @@ int acpi_bus_update_power(acpi_handle ha
> >  	if (result)
> >  		return result;
> >  
> > -	result = __acpi_bus_set_power(device, state);
> > +	result = acpi_device_set_power(device, state);
> >  	if (!result && state_p)
> >  		*state_p = state;
> >  
> > Index: linux/include/acpi/acpi_bus.h
> > ===================================================================
> > --- linux.orig/include/acpi/acpi_bus.h
> > +++ linux/include/acpi/acpi_bus.h
> > @@ -338,6 +338,7 @@ acpi_status acpi_bus_get_status_handle(a
> >  				       unsigned long long *sta);
> >  int acpi_bus_get_status(struct acpi_device *device);
> >  int acpi_bus_set_power(acpi_handle handle, int state);
> > +int acpi_device_set_power(struct acpi_device *device, int state);
> >  int acpi_bus_update_power(acpi_handle handle, int *state_p);
> >  bool acpi_bus_power_manageable(acpi_handle handle);
> >  bool acpi_bus_can_wakeup(acpi_handle handle);
> > @@ -482,6 +483,16 @@ static inline int acpi_pm_device_sleep_w
> >  }
> >  #endif
> >  
> > +static inline bool acpi_device_power_manageable(struct acpi_device *adev)
> > +{
> > +	return adev->flags.power_manageable;
> > +}
> > +
> > +static inline bool acpi_device_can_wakeup(struct acpi_device *adev)
> > +{
> > +	return adev->wakeup.flags.valid;
> > +}
> > +
> >  #else	/* CONFIG_ACPI */
> >  
> >  static inline int register_acpi_bus_type(void *bus) { return 0; }
> > 
> --
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> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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