From 362b646062b2073bd5c38efb42171d86e4f717e6 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Fri, 4 Nov 2011 03:33:46 +0100 Subject: [PATCH] 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 Acked-by: Rafael J. Wysocki Signed-off-by: Len Brown --- Documentation/ABI/stable/sysfs-acpi-pmprofile | 22 +++++++++++++++++++ drivers/acpi/sysfs.c | 14 +++++++++++- 2 files changed, 35 insertions(+), 1 deletion(-) 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 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; } -- 2.20.1