blob: 98fe5c3331214df8745ba8fab3e25875bdec7f8f (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
.. SPDX-License-Identifier: GPL-2.0
===========================
ACPI Fan Performance States
===========================
When the optional _FPS object is present under an ACPI device representing a
fan (for example, PNP0C0B or INT3404), the ACPI fan driver creates additional
"state*" attributes in the sysfs directory of the ACPI device in question.
These attributes list properties of fan performance states.
For more information on _FPS refer to the ACPI specification at:
http://uefi.org/specifications
For instance, the contents of the INT3404 ACPI device sysfs directory
may look as follows::
$ ls -l /sys/bus/acpi/devices/INT3404:00/
total 0
...
-r--r--r-- 1 root root 4096 Dec 13 20:38 state0
-r--r--r-- 1 root root 4096 Dec 13 20:38 state1
-r--r--r-- 1 root root 4096 Dec 13 20:38 state10
-r--r--r-- 1 root root 4096 Dec 13 20:38 state11
-r--r--r-- 1 root root 4096 Dec 13 20:38 state2
-r--r--r-- 1 root root 4096 Dec 13 20:38 state3
-r--r--r-- 1 root root 4096 Dec 13 20:38 state4
-r--r--r-- 1 root root 4096 Dec 13 20:38 state5
-r--r--r-- 1 root root 4096 Dec 13 20:38 state6
-r--r--r-- 1 root root 4096 Dec 13 20:38 state7
-r--r--r-- 1 root root 4096 Dec 13 20:38 state8
-r--r--r-- 1 root root 4096 Dec 13 20:38 state9
-r--r--r-- 1 root root 4096 Dec 13 01:00 status
...
where each of the "state*" files represents one performance state of the fan
and contains a colon-separated list of 5 integer numbers (fields) with the
following interpretation::
control_percent:trip_point_index:speed_rpm:noise_level_mdb:power_mw
* ``control_percent``: The percent value to be used to set the fan speed to a
specific level using the _FSL object (0-100).
* ``trip_point_index``: The active cooling trip point number that corresponds
to this performance state (0-9).
* ``speed_rpm``: Speed of the fan in rotations per minute.
* ``noise_level_mdb``: Audible noise emitted by the fan in this state in
millidecibels.
* ``power_mw``: Power draw of the fan in this state in milliwatts.
For example::
$cat /sys/bus/acpi/devices/INT3404:00/state1
25:0:3200:12500:1250
When a given field is not populated or its value provided by the platform
firmware is invalid, the "not-defined" string is shown instead of the value.
|
