This file defines the events that dictate how fan control operates. Each event can contain groups, triggers, and actions.
Actions are where fan targets are calculated and set, among other things. Triggers specify when an action should run. Groups specify which D-Bus objects the triggers and actions should operate on.
Some actions have modifiers, which help calculate a value.
[ { "name": "fan(s) missing", "groups": [ { "name": "fan inventory", "interface": "xyz.openbmc_project.Inventory.Item", "property": { "name": "Present" } } ], "triggers": [ { "class": "init", "method": "get_properties" }, { "class": "signal", "signal": "properties_changed" } ], "actions": [ { "name": "count_state_before_target", "count": 1, "state": false, "target": 15000 } ] } ]
The above event is an example of a method to set the fan target to 15000 when one or more fans is missing. The basic behavior with this config is:
The trigger init.get_properties will, on fan control startup, read the Present property on the xyz.openbmc_project.Inventory.Item interface from every D-Bus object in the 'fan inventory' group, update those values in the object cache, and then call the count_state_before_target action.
The trigger signal.properties_changed will watch for changes on the Present property on each D-Bus object in the group, update the new value in the object cache, and call the count_state_before_target action when the value changes.
The count_state_before_target action will look at the object cache value of the Present property on each member of the group and set the fan target hold to 15000 when one or more of them is false. Otherwise, it will clear its fan target hold.
"groups": [ { "name": "<name>", "interface": "<interface>", "property": { "name": "<name>" } } ... ]
The name of a group that must be also be defined in groups.json.
The actions and triggers defined with this group will look at this D-Bus interface on the members of this group.
The actions and triggers defined with this group will look at this D-Bus property on the members of this group.
There are several classes of triggers, and the JSON configuration is different for each.
Init triggers run when fan control events are enabled on fan control startup. After invoking the configured method, any actions configured for this trigger will run.
{ "class": "init", "method": "<method>" }
get_properties - Read the property configured for the group from every member of the group, and store it in fan control's object cache.
name_has_owner - Populates the service owned state from D-Bus for each group member in fan control's D-Bus service cache map.
Signal triggers subscribe to certain D-Bus signals for each member of its configured group. After handling the signal, any configured actions are run.
{ "class": "signal", "signal": "<signal>" }
properties_changed - Subscribes to the PropertiesChanged signal for the D-Bus interface and property specified in the group definition for each group member. When the signal occurs, the new property value will be added to or updated in the object cache.
interfaces_added - Subscribes to the InterfacesAdded signal for the D-Bus interface specified in the group definition for each group member. When the signal occurs, the interface and its properties will be added to the object cache.
interfaces_removed - Subscribes to the InterfacesRemoved signal for the D-Bus interface specified in the group definition for each group member. When the signal occurs, the interface and properties will be removed from the object cache.
name_owner_changed - Subscribes to the NameOwnerChanged signal for the services that host the D-bus interface specified in the group definition for each group member. When the signal occurs, the service owned state will be updated in the service cache map.
member - Subscribes to the signal listed on each group member. No caches are updated when the signal occurs.
Timer triggers run actions after the configured type of timer expires.
{ "class": "timer", "type": "<type>", "interval": "<interval>", "preload_groups": "<true/false>" }
oneshot - Starts a timer that runs once.
repeating - Starts a repeating timer.
The timer length in microseconds
Optional, if set to true, will update the D-Bus properties from the configured groups in the object cache after the timer expires but before any actions run.
Parameter triggers run actions after a parameter changes.
{ "class": "parameter", "parameter": "<parameter>" }
The parameter value to watch.
PowerOn triggers run when the power turns on. Functionally, they behave like an init trigger.
{ "class": "poweron", "method": "<method>" }
The methods are the same as with the init trigger.
PowerOff triggers run when the power turns off. Functionally, they behave like an init trigger.
{ "class": "poweroff", "method": "<method>" }
The methods are the same as with the init trigger.
Actions can either operate on the groups listed with the event, or on the groups listed within the action's JSON config.
Most actions set fan targets or floors. This can be done by requesting a target value explicitly, or by requesting an increase or decrease delta. Targets and floors can also be set with a hold, meaning another action can't set a floor/target below the one that is held.
Some actions set or read a key/value pair called a parameter. These can be created, updated, and deleted as necessary. For example, one action may calculate and set a floor_index parameter, and another action may then read that parameter to help choose a fan floor.
The available actions are:
Calculates the net target increase to be requested based on the value of each property given within a group. The net target increase is based on the maximum difference between the delta JSON value and all of the properties of the group. The final result is the increase change that's requested to the current target of a zone.
The group values can be compared to either a value hardcoded in the JSON, or a parameter value.
{ "name": "set_net_increase_target", "groups": [ { "name": "pcie temps", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "state": 70.0, "delta": 255 }
The above config uses a hardcoded state value:
For each member of the 'pcie temps' group:
Requests an increase of the largest calculated delta value, if there is one.
{ "name": "set_net_increase_target", "groups": [ { "name": "proc0 core temps", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "state_parameter_name": "proc_0_core_dvfs_increase_temp", "delta": 300 }
The above config uses a parameter as the state value:
For each member of the 'proc 0 core temps' group:
Requests an increase of the largest calculated delta value, if there is one.
Calculates the net target decrease to be requested based on the value of each property given within a group. The net target decrease is based on the minimum difference between the delta JSON value and all properties in the group. The final result is the decrease change that's requested to the current target of a zone.
The group values can be compared to either a value hardcoded in the JSON, or a parameter value.
{ "name": "set_net_decrease_target", "groups": [ { "name": "pcie temps", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "state": 65.0, "delta": 80 }
The above config uses a hardcoded state value:
For each member of the 'pcie temps' group:
Requests a decrease of the smallest calculated delta value, if there is one.
{ "name": "set_net_decrease_target", "groups": [ { "name": "proc 0 core temps", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "state_parameter_name": "proc_0_core_dvfs_decrease_temp", "delta": 50 }
The above config uses a parameter as the state value:
For each member of the 'proc 0 core temps' group:
Requests a decrease of the smallest calculated delta value, if there is one.
Sets the fans to a configured floor when a number of members within the group are at a configured state. Once the number of members at the given state falls below the configured count, the floor hold is released.
{ "name": "count_state_floor", "count": 2, "state": false, "floor": 18000, "delay": 3 }
The above config reads the configured D-Bus property on each group member configured for the action. If two or more members have a property value of false for 3 seconds, a floor hold will be requested with a value of 18000. Otherwise, the floor hold will be released (if it was previously requested).
Sets the fans to a configured target when a number of members within the group are at a configured state. Once the number of members at the given state falls below the configured count, active fan target changes are allowed.
{ "name": "count_state_before_target", "count": 1, "state": false, "target": 18000 }
The above config reads the configured D-Bus property on each group member configured for the action. If one or more members have a property value of false, a target hold will be requested with a value of 18000. Otherwise, the hold will be released (if it was previously requested).
Sets the fan floor to the defined zone's default fan floor when a service associated to a given group has terminated. Once all services are functional and providing the sensors, the fan floor is allowed to be set normally again.
There is no additional JSON config for this action.
This action can be used to set a floor value based on 2 or more groups having values within certain ranges, where the key group chooses the set of tables in which to check the remaining group values.
{ "name": "mapped_floor", "key_group": "ambient temp", "default_floor": 5555, "fan_floors": [ { "key": 25, "default_floor": 4444, "floor_offset_parameter": "ambient_25_altitude_offset", "floors": [ { "parameter": "pcie_floor_index", "floors": [ { "value": 1, "floor": 2000 }, { "value": 2, "floor": 3000 }, { "value": 3, "floor": 4000 }, { "value": 4, "floor": 5000 }, { "value": 5, "floor": 6000 } ] }, { "group": "power save", "floors": [{ "value": true, "floor": 1000 }] } ] } ] }
The above config will use the maximum value of the 'ambient temp' group as the key into the 'fan_floors' tables. There is one of those tables listed, and it will be used when the key group has a max value of less than 25.
It will then traverse the contained floors arrays, keeping track of the highest valid floor value it finds. If it doesn't find any valid floor values, it will use the default_floor value of 4444, though that value is optional.
If no valid tables were found given the key value, the default_floor value of 5555 would be used, though that is optional and if not supplied the code would default to the default floor of the zone.
At the end of the analysis, a floor hold will be set with the final floor value.
This action can also have a condition specified where a group property must either match or not match a given value to determine if the action should run or not. This requires the following in the JSON:
For example, the following says the single member of the 'cpu 0' group must have its Model property be equal to "1234" for the action to run:
"groups": [{ "name": "cpu 0", "interface": "xyz.openbmc_project.Inventory.Decorator.Asset", "property": { "name": "Model" } } ... ], ... "name": "mapped_floor", "key_group": "ambient temp", "condition_group": "cpu 0", "condition_value": "1234", "condition_op": "equal", ...
Sets the fans to a configured target when any service owner associated to the group is missing. Once all services are functional and providing all the group data again, active fan target changes are allowed.
{ "name": "set_target_on_missing_owner", "groups": [ { "name": "fan inventory", "interface": "xyz.openbmc_project.Inventory.Item", "property": { "name": "Present" } } ], "target": 18000 }
The above config will set a target hold of 18000 when the service associated with the 'fan inventory' group is lost.
This action locks fans at configured targets when the configured count amount of fans meet criterion for the particular condition. A locked fan maintains its override target until unlocked (or locked at a higher target). Upon unlocking, it will either revert to temperature control or activate the next-highest target remaining in its list of locks.
{ "name": "override_fan_target", "count": 1, "state": false, "fans": ["fan0", "fan1", "fan2", "fan3"], "target": 10000 }
The above config will lock all fans in the fans array at a target of 10000 when one or more members in its configured group have a group property value of false.
This could be used for example, to lock the rotors of a multirotor fan to a high target when one of its rotors has a functional property equal to false.
Sets the pcie_floor_index parameter based on the current configuration of plugged and powered on PCIe cards, using data from the pcie_cards.json file.
It chooses the highest index from the active PCIe cards to set in the parameter.
It must be configured with the following groups and properties:
{ "name": "pcie_card_floors", "use_config_specific_files": true, "settle_time": 2 }
The use_config_specific_files field tells the code to look for the 'pcie_cards.json' files in the same system specific directories as 'events.json'. If missing or false, looks in the base fan control directory.
The settle_time field is the amount of time in seconds that needs to pass without a call to run() from a group property value changing. As the PCIeDevice attributes are written close together by the host, this allows the action to wait until the writes are done before selecting the index.
Additional details are in the header file
Determines the maximum value from the properties of the group of D-Bus objects and sets the requested target base to this value. Only positive integer or floating point types are supported as these are the only valid types for a fan target to be based off of.
The requested target base value is the base value to apply a target delta to. By default, it's the current zone target unless modified by this action.
{ "name": "set_request_target_base_with_max", "groups": [ { "name": "fan targets", "interface": "xyz.openbmc_project.Fan.Target", "property": { "name": "Target" } } ] }
The above config will set the requested target base to the maximum Target property value of all members of the 'fan targets' group.
Sets a parameter value based on the maximum group property value. The property value can be modified before storing it if the JSON specifies a valid modifier expression.
{ "name": "set_parameter_from_group_max", "parameter_name": "proc_0_throttle_temp", "modifier": { "expression": "minus", "value": 4 } }
The above config will first find the max of its groups property values, subtract 4, and then store the resulting value in the proc_0_throttle_temp parameter.
The action sets target of Zone to a value corresponding to the maximum value from maximum group property value. The mapping is based on a provided table. If there are more than one event using this action, the maximum speed derived from the mapping of all groups will be set to the zone's target.
{ "name": "target_from_group_max", "groups": [ { "name": "zone0_ambient", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "neg_hysteresis": 1, "pos_hysteresis": 0, "map": [ { "value": 10.0, "target": 38.0 } ] }
The above JSON will cause the action to read the property specified in the group "zone0_ambient" from all members of the group. The change in the group's members value will be checked against "neg_hysteresis" and "pos_hysteresis" to decide if it is worth taking action. "pos_hysteresis" is for the increasing case and "neg_hysteresis" is for the decreasing case. The maximum property value in the group will be mapped to the "map" to get the output "target". Each configured event using this action will be provided with a key in a static map to store its mapping result. The static map will be shared across the events of this action. Therefore, the updated "target" value derived from "zone0_ambient" will be stored in that static map with its own key. Each time it calls this action running for each event, after the new value is updated to the static map, the maximum value from it will be used to set to the Zone's target.
This action starts and stops a timer that runs a list of actions whenever the timer expires. A timer can be either oneshot or repeating.
When all groups have a configured value to compare against, that will be compared against all members within each group to start/stop the timer. When all group members have a given value and it matches what's in the cache, the timer is started and if any do not match, the timer is stopped.
When any group does not have a configured value to be compared against, the groups' service owned state is used to start/stop the timer. When any service providing a group member is not owned, the timer is started and if all members' services are owned, the timer is stopped.
Consider the following action config:
{ "name": "call_actions_based_on_timer", "timer": { "interval": 5000000, "type": "oneshot" }, "actions": [ { "name": "test" } ] }
If its group configuration has a property value listed, like:
{ "name": "fan inventory", "interface": "xyz.openbmc_project.Inventory.Item", "property": { "name": "Present", "value": true } }
Then a oneshot timer of 5000000us will be started when every member of the fan inventory group has a value of true. Otherwise, the timer will be stopped if it's running.
If the group configuration has no property value listed, like:
{ "name": "fan inventory", "interface": "xyz.openbmc_project.Inventory.Item", "property": { "name": "Present" } }
Then the timer will be started when any service providing a group member isn't owned (on D-Bus). Otherwise, it will stop the timer if it's running.
This action adds the members of its groups to the object cache by using the GetManagedObjects D-Bus method to find and add the results. When that is done, it then runs any actions listed in the JSON.
This allows an action to run with the latest values in the cache without having to subscribe to propertiesChanged for them all.
{ "name": "get_managed_objects", "groups": [ { "name": "proc temps", "interface": "xyz.openbmc_project.Sensor.Value", "property": { "name": "Value" } } ], "actions": [ { "name": "set_net_increase_target", "state": 30, "delta": 100 } ] }
The above config will make the GetManagedObjects call on all services that own the configured groups and then add all resulting property values to the object cache. After that, it will call the set_net_increase_target action using the same groups.
Modifiers are used by some actions to help calculate values.
Subtract the value field from the passed in value.
"modifier": { "expression": "minus", "value": 4 }
The above config subtracts 4 from what is passed to it.
Returns a value from a data table that is selected when the argument passed in is less than the arg_value entry in the table row. If there is a default_value field supplied, then that will be returned if the argument is greater than the arg_value of the last row.
"modifier": { "operator": "less_than", "default_value": 10000, "value": [ { "arg_value": 500, "parameter_value": 1 }, { "arg_value": 1000, "parameter_value": 2 }, { "arg_value": 1500, "parameter_value": 3 } ] }
The above config returns 1 if the arg passed is less than 500, 2 if less than 1000, and 3 if less than 1500. Otherwise returns 10000, the default value.