No description
Find a file
Srinivas Pandruvada d19e470b66 ACPI: fan: Expose fan performance state information
When _FPS indicates variable speed fan support, the thermal cooling
device for fan shows max performance state count as "max_state"
(greater than or equal to 1).

But the thermal cooling device doesn't expose the properties of each
performance state. This is not enough for smart fan control user
space software, which also considers speed, power and noise level.

This change exposes the properties of the fan performance states
in the sysfs directory of the ACPI device representing the fan,
that is

/sys/bus/acpi/devices/devices/INT3404:00

or

/sys/bus/platform/devices/PNP0C0B:00.

For example:

$ ls /sys/bus/acpi/devices/INT3404\:00
description  path           state0   state11  state4  state7  status
hid          physical_node  state1   state2   state5  state8  subsystem
modalias     power          state10  state3   state6  state9  uevent
uid          wakeup

where each state* attribute lists the properties of a fan performance
state in the following format:

control_percent:trip_point:speed_rpm:noise_level_mdb:power_mw

$ cat /sys/bus/acpi/devices/INT3404\:00/state10
95:0:11600:47500:4500

as documented in

Documentation/admin-guide/acpi/fan_performance_states.rst

While at it, return the correct error code from acpi_fan_probe()
when acpi_fan_get_fps() or acpi_fan_get_fif() fails.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject, changelog, documentation ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-12-19 22:35:04 +01:00
arch RISC-V updates for v5.5-rc2 2019-12-15 12:27:31 -08:00
block for-linus-20191212 2019-12-13 14:27:19 -08:00
certs
crypto
Documentation ACPI: fan: Expose fan performance state information 2019-12-19 22:35:04 +01:00
drivers ACPI: fan: Expose fan performance state information 2019-12-19 22:35:04 +01:00
fs Merge branch 'remove-ksys-mount-dup' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo/linux 2019-12-15 11:36:12 -08:00
include Pull request for 5.5-rc2 2019-12-15 14:58:13 -08:00
init
ipc
kernel treewide conversion from FIELD_SIZEOF() to sizeof_field() 2019-12-13 14:02:12 -08:00
lib
LICENSES
mm
net io_uring-5.5-20191212 2019-12-13 14:24:54 -08:00
samples
scripts
security
sound sound fixes for 5.5-rc2 2019-12-13 14:40:38 -08:00
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS overlayfs fixes for 5.5-rc2 2019-12-14 11:13:54 -08:00
Makefile Linux 5.5-rc2 2019-12-15 15:16:08 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.