diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 12:32:11 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 12:32:11 -0400 |
commit | c11f6c82581e8be4e1829c677db54e7f55cebece (patch) | |
tree | 1a116241b0831ded998aabe800bdc24104cbd826 /Documentation/hwmon | |
parent | 40aba218969914d1b225e742617adb921cf94eae (diff) | |
parent | 193a6dec1c0246a80b6d0101e4f351ccf877bcac (diff) |
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (119 commits)
ACPI: don't pass handle for fixed hardware notifications
ACPI: remove null pointer checks in deferred execution path
ACPI: simplify deferred execution path
acerhdf: additional BIOS versions
acerhdf: convert to dev_pm_ops
acerhdf: fix fan control for AOA150 model
thermal: add missing Kconfig dependency
acpi: switch /proc/acpi/{debug_layer,debug_level} to seq_file
hp-wmi: fix rfkill memory leak on unload
ACPI: remove unnecessary #ifdef CONFIG_DMI
ACPI: linux/acpi.h should not include linux/dmi.h
hwmon driver for ACPI 4.0 power meters
topstar-laptop: add new driver for hotkeys support on Topstar N01
thinkpad_acpi: fix rfkill memory leak on unload
thinkpad-acpi: report brightness events when required
thinkpad-acpi: don't poll by default any of the reserved hotkeys
thinkpad-acpi: Fix procfs hotkey reset command
thinkpad-acpi: deprecate hotkey_bios_mask
thinkpad-acpi: hotkey poll fixes
thinkpad-acpi: be more strict when detecting a ThinkPad
...
Diffstat (limited to 'Documentation/hwmon')
-rw-r--r-- | Documentation/hwmon/acpi_power_meter | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/Documentation/hwmon/acpi_power_meter b/Documentation/hwmon/acpi_power_meter new file mode 100644 index 000000000000..c80399a00c50 --- /dev/null +++ b/Documentation/hwmon/acpi_power_meter | |||
@@ -0,0 +1,51 @@ | |||
1 | Kernel driver power_meter | ||
2 | ========================= | ||
3 | |||
4 | This driver talks to ACPI 4.0 power meters. | ||
5 | |||
6 | Supported systems: | ||
7 | * Any recent system with ACPI 4.0. | ||
8 | Prefix: 'power_meter' | ||
9 | Datasheet: http://acpi.info/, section 10.4. | ||
10 | |||
11 | Author: Darrick J. Wong | ||
12 | |||
13 | Description | ||
14 | ----------- | ||
15 | |||
16 | This driver implements sensor reading support for the power meters exposed in | ||
17 | the ACPI 4.0 spec (Chapter 10.4). These devices have a simple set of | ||
18 | features--a power meter that returns average power use over a configurable | ||
19 | interval, an optional capping mechanism, and a couple of trip points. The | ||
20 | sysfs interface conforms with the specification outlined in the "Power" section | ||
21 | of Documentation/hwmon/sysfs-interface. | ||
22 | |||
23 | Special Features | ||
24 | ---------------- | ||
25 | |||
26 | The power[1-*]_is_battery knob indicates if the power supply is a battery. | ||
27 | Both power[1-*]_average_{min,max} must be set before the trip points will work. | ||
28 | When both of them are set, an ACPI event will be broadcast on the ACPI netlink | ||
29 | socket and a poll notification will be sent to the appropriate | ||
30 | power[1-*]_average sysfs file. | ||
31 | |||
32 | The power[1-*]_{model_number, serial_number, oem_info} fields display arbitrary | ||
33 | strings that ACPI provides with the meter. The measures/ directory contains | ||
34 | symlinks to the devices that this meter measures. | ||
35 | |||
36 | Some computers have the ability to enforce a power cap in hardware. If this is | ||
37 | the case, the power[1-*]_cap and related sysfs files will appear. When the | ||
38 | average power consumption exceeds the cap, an ACPI event will be broadcast on | ||
39 | the netlink event socket and a poll notification will be sent to the | ||
40 | appropriate power[1-*]_alarm file to indicate that capping has begun, and the | ||
41 | hardware has taken action to reduce power consumption. Most likely this will | ||
42 | result in reduced performance. | ||
43 | |||
44 | There are a few other ACPI notifications that can be sent by the firmware. In | ||
45 | all cases the ACPI event will be broadcast on the ACPI netlink event socket as | ||
46 | well as sent as a poll notification to a sysfs file. The events are as | ||
47 | follows: | ||
48 | |||
49 | power[1-*]_cap will be notified if the firmware changes the power cap. | ||
50 | power[1-*]_interval will be notified if the firmware changes the averaging | ||
51 | interval. | ||