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Commit 362b6460 authored by Thomas Renninger's avatar Thomas Renninger Committed by Len Brown
Browse files

ACPI: Export FADT pm_profile integer value to userspace 



There are a lot userspace approaches to detect the usage of the
platform (laptop, workstation, server, ...) and adjust kernel tunables
accordingly (io/process scheduler, power management, ...).

These approaches need constant maintaining and are ugly to implement
(detect PCMCIA controller -> laptop,
does not work on recent systems anymore, ...)
On ACPI systems there is an easy and reliable way (if implemented
in BIOS and most recent platforms have this value set).
-> export it to userspace.

Signed-off-by: default avatarThomas Renninger <trenn@suse.de>
Acked-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent c3b92c87

Documentation/ABI/stable/sysfs-acpi-pmprofile

0 → 100644
+22 −0
Original line number Original line Diff line number Diff line 
What: 		/sys/firmware/acpi/pm_profile

Date:		03-Nov-2011

KernelVersion:	v3.2

Contact:	linux-acpi@vger.kernel.org

Description: 	The ACPI pm_profile sysfs interface exports the platform

		power management (and performance) requirement expectations

		as provided by BIOS. The integer value is directly passed as

		retrieved from the FADT ACPI table.

Values:         For possible values see ACPI specification:

		5.2.9 Fixed ACPI Description Table (FADT)

		Field: Preferred_PM_Profile



		Currently these values are defined by spec:

		0 Unspecified

		1 Desktop

		2 Mobile

		3 Workstation

		4 Enterprise Server

		5 SOHO Server

		6 Appliance PC

		7 Performance Server

		>7 Reserved

drivers/acpi/sysfs.c

+13 −1
Original line number Original line Diff line number Diff line
@@ -706,11 +706,23 @@ static void __exit interrupt_stats_exit(void) 
	return;

	return;

}

}





static ssize_t

acpi_show_profile(struct device *dev, struct device_attribute *attr,

		  char *buf)

{

	return sprintf(buf, "%d\n", acpi_gbl_FADT.preferred_profile);

}



static const struct device_attribute pm_profile_attr =

	__ATTR(pm_profile, S_IRUGO, acpi_show_profile, NULL);



int __init acpi_sysfs_init(void)

int __init acpi_sysfs_init(void)

{

{

	int result;

	int result;





	result = acpi_tables_sysfs_init();

	result = acpi_tables_sysfs_init();



	if (result)

		return result;

	result = sysfs_create_file(acpi_kobj, &pm_profile_attr.attr);

	return result;

	return result;

}
 
}