On Friday, November 04, 2011, Thomas Renninger wrote:
> 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
This is for Len, I guess?
Acked-by: Rafael J. Wysocki <rjw@xxxxxxx>
Thanks,
Rafael
> ---
> 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;
> }
>
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