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| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2022-02-11 19:09:32 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-02-25 22:49:30 +0300 |
| commit | 0750b8fcf313845b21c71344b4bea8ad7d3cee84 (patch) | |
| tree | 1dc5b01c635c52472e099b7ed8415f29c6ccf8db /Documentation | |
| parent | f1197343f07749035d74c08cf8b546c4f95614ab (diff) | |
| download | linux-0750b8fcf313845b21c71344b4bea8ad7d3cee84.tar.xz | |
Documentation/admin-guide/acpi: Add documentation for fine grain control
Add documentation for the newly added attributes:
fine_grain_control
fan_speed_rpm
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/acpi/fan_performance_states.rst | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/admin-guide/acpi/fan_performance_states.rst b/Documentation/admin-guide/acpi/fan_performance_states.rst index 98fe5c333121..b9e4b4d146c1 100644 --- a/Documentation/admin-guide/acpi/fan_performance_states.rst +++ b/Documentation/admin-guide/acpi/fan_performance_states.rst @@ -60,3 +60,31 @@ For example:: 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. + +ACPI Fan Fine Grain Control +============================= + +When _FIF object specifies support for fine grain control, then fan speed +can be set from 0 to 100% with the recommended minimum "step size" via +_FSL object. User can adjust fan speed using thermal sysfs cooling device. + +Here use can look at fan performance states for a reference speed (speed_rpm) +and set it by changing cooling device cur_state. If the fine grain control +is supported then user can also adjust to some other speeds which are +not defined in the performance states. + +The support of fine grain control is presented via sysfs attribute +"fine_grain_control". If fine grain control is present, this attribute +will show "1" otherwise "0". + +This sysfs attribute is presented in the same directory as performance states. + +ACPI Fan Performance Feedback +============================= + +The optional _FST object provides status information for the fan device. +This includes field to provide current fan speed in revolutions per minute +at which the fan is rotating. + +This speed is presented in the sysfs using the attribute "fan_speed_rpm", +in the same directory as performance states. |