Callback Manager

Author: James Feist !jfei

Primary assignee: James Feist !jfei

Other contributors: None

Created: 2019-06-26

Problem Description

We need a centralized location to change the LED state.

Background and References

Redfish Health

Sensor Thresholds

Requirements

Need to be able to trigger the LED from multiple locations and maintain state.

Proposed Design

The callback manager can change LED state in the below ways.

1. Monitoring the sensor threshold interface.
2. Monitoring critical / warning thresholds as Redfish does.

Other interfaces specific interfaces can be added later if it makes sense. The reason it was designed this way is Redfish has the idea of a Global health state, and a component health state. We need to map these to the LED.

Thresholds

Warning thresholds will trigger warning (blink green) LED state.

Critical thresholds will trigger critical (blink amber) state.

Callback manager will create associations for redfish for thresholds automatically.

Associations

There are two types of status associations, detailed in the Redfish health whitepaper.

1. Global- These are the attributes to the global state (warning / critical). This is exposed by the callback manager for ease (xyz.openbmc_project.Inventory.Item.Global, path=/xyz/openbmc_project/CallbackManager)
2. Local- Any other warning / critical association.

If the path for an association is Critical for Global & Local, the LED will be in the fatal (amber solid) state.

If the path for an association is in Warning for Global & Critical for local, the LED will be in the Critical (amber blink) state.

If the path for an association is in the Warning for Global & not Critical for local, the LED will be in the Warning (blink green) state.

Alternatives Considered

Write the LED manually, this seems very error prone.

Impacts

Will have to add more associations.

Testing

Sensor override, then look at LED and Redfish.