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ACPI: Export FADT pm_profile integer value to userspace

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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: Thomas Renninger <trenn@suse.de>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Thomas Renninger 2011-11-04 03:33:46 +01:00 committed by Len Brown
parent c3b92c8787
commit 362b646062
2 changed files with 35 additions and 1 deletions
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22
Documentation/ABI/stable/sysfs-acpi-pmprofile Normal file
View file

@ -0,0 +1,22 @@
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

14
drivers/acpi/sysfs.c
View file

@ -706,11 +706,23 @@ static void __exit interrupt_stats_exit(void)
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 result;
result = acpi_tables_sysfs_init();
if (result)
return result;
result = sysfs_create_file(acpi_kobj, &pm_profile_attr.attr);
return result;
}