diff options
| author | Shinji Nomoto <fj5851bi@fujitsu.com> | 2025-05-20 15:27:04 +0900 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2025-05-20 06:19:25 -0700 |
| commit | 46d40b2479ab6417db4d7174f7a938c994435b3f (patch) | |
| tree | ecd78737ebbd69d6722ce2acb1dc2b9e98154fb9 | |
| parent | b2446a16dbf2347a07af0cf994ca36576d94df77 (diff) | |
doc: hwmon: acpi_power_meter: Add information about enabling the power capping feature.
To enable the power capping feature of the acpi_power_meter driver on
systems other than IBM products, you must explicitly specify
the force_cap_on module parameter.
Add information to the documentation about enabling the power capping
feature with this driver, including the above, to improve user convenience.
Signed-off-by: Shinji Nomoto <fj5851bi@fujitsu.com>
Link: https://lore.kernel.org/r/20250520062707.1657667-1-fj5851bi@fujitsu.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | Documentation/hwmon/acpi_power_meter.rst | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/Documentation/hwmon/acpi_power_meter.rst b/Documentation/hwmon/acpi_power_meter.rst index 8628c1161015..a91403a2a26f 100644 --- a/Documentation/hwmon/acpi_power_meter.rst +++ b/Documentation/hwmon/acpi_power_meter.rst @@ -37,9 +37,16 @@ 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 +the case, the `power[1-*]_cap` and related sysfs files will appear. +For information on enabling the power cap feature, refer to the description +of the "force_on_cap" option in the "Module Parameters" chapter. +To use the power cap feature properly, you need to set appropriate value +(in microWatts) to the `power[1-*]_cap` sysfs files. +The value must be within the range between the minimum value at `power[1-]_cap_min` +and the maximum value at `power[1-]_cap_max (both in microWatts)`. + +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. @@ -52,3 +59,19 @@ 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. + +Module Parameters +----------------- + +* force_cap_on: bool + Forcefully enable the power capping feature to specify + the upper limit of the system's power consumption. + + By default, the driver's power capping feature is only + enabled on IBM products. + Therefore, on other systems that support power capping, + you will need to use the option to enable it. + + Note: power capping is potentially unsafe feature. + Please check the platform specifications to make sure + that capping is supported before using this option. |