diff options
| author | Thomas Renninger | 2011-11-04 03:33:46 +0100 |
|---|---|---|
| committer | Len Brown | 2011-11-06 20:48:42 -0500 |
| commit | 362b646062b2073bd5c38efb42171d86e4f717e6 (patch) | |
| tree | 6c98cdb7aa5d9be22e2b24ca06b822455ef4b9f5 | |
| parent | c3b92c8787367a8bb53d57d9789b558f1295cc96 (diff) | |
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: Thomas Renninger <trenn@suse.de>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>
| -rw-r--r-- | Documentation/ABI/stable/sysfs-acpi-pmprofile | 22 | ||||
| -rw-r--r-- | drivers/acpi/sysfs.c | 14 |
2 files changed, 35 insertions, 1 deletions
diff --git a/Documentation/ABI/stable/sysfs-acpi-pmprofile b/Documentation/ABI/stable/sysfs-acpi-pmprofile new file mode 100644 index 000000000000..964c7a8afb26 --- /dev/null +++ b/Documentation/ABI/stable/sysfs-acpi-pmprofile @@ -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 diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index c538d0ef10ff..9f66181c814e 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -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; } |