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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 09:32:11 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-23 09:32:11 -0700 |
commit | c11f6c82581e8be4e1829c677db54e7f55cebece (patch) | |
tree | 1a116241b0831ded998aabe800bdc24104cbd826 /Documentation/hwmon | |
parent | 40aba218969914d1b225e742617adb921cf94eae (diff) | |
parent | 193a6dec1c0246a80b6d0101e4f351ccf877bcac (diff) | |
download | lwn-c11f6c82581e8be4e1829c677db54e7f55cebece.tar.gz lwn-c11f6c82581e8be4e1829c677db54e7f55cebece.zip |
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 @@ +Kernel driver power_meter +========================= + +This driver talks to ACPI 4.0 power meters. + +Supported systems: + * Any recent system with ACPI 4.0. + Prefix: 'power_meter' + Datasheet: http://acpi.info/, section 10.4. + +Author: Darrick J. Wong + +Description +----------- + +This driver implements sensor reading support for the power meters exposed in +the ACPI 4.0 spec (Chapter 10.4). These devices have a simple set of +features--a power meter that returns average power use over a configurable +interval, an optional capping mechanism, and a couple of trip points. The +sysfs interface conforms with the specification outlined in the "Power" section +of Documentation/hwmon/sysfs-interface. + +Special Features +---------------- + +The power[1-*]_is_battery knob indicates if the power supply is a battery. +Both power[1-*]_average_{min,max} must be set before the trip points will work. +When both of them are set, an ACPI event will be broadcast on the ACPI netlink +socket and a poll notification will be sent to the appropriate +power[1-*]_average sysfs file. + +The power[1-*]_{model_number, serial_number, oem_info} fields display arbitrary +strings that ACPI provides with the meter. The measures/ directory contains +symlinks to the devices that this meter measures. + +Some computers have the ability to enforce a power cap in hardware. If this is +the case, the power[1-*]_cap and related sysfs files will appear. When the +average power consumption exceeds the cap, an ACPI event will be broadcast on +the netlink event socket and a poll notification will be sent to the +appropriate power[1-*]_alarm file to indicate that capping has begun, and the +hardware has taken action to reduce power consumption. Most likely this will +result in reduced performance. + +There are a few other ACPI notifications that can be sent by the firmware. In +all cases the ACPI event will be broadcast on the ACPI netlink event socket as +well as sent as a poll notification to a sysfs file. The events are as +follows: + +power[1-*]_cap will be notified if the firmware changes the power cap. +power[1-*]_interval will be notified if the firmware changes the averaging +interval. |