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@xxxxxxx>
CC: lenb@xxxxxxxxxx
---
Documentation/ABI/stable/sysfs-acpi-pmprofile | 22 ++++++++++++++++++++++
drivers/acpi/sysfs.c | 14 +++++++++++++-
2 files changed, 35 insertions(+), 1 deletions(-)
create mode 100644 Documentation/ABI/stable/sysfs-acpi-pmprofile
diff --git a/Documentation/ABI/stable/sysfs-acpi-pmprofile b/Documentation/ABI/stable/sysfs-acpi-pmprofile
new file mode 100644
index 0000000..964c7a8
--- /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@xxxxxxxxxxxxxxx
+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 c538d0e..9f66181 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;
}
--
1.7.6.1
--
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