phosphor-power-sequencer/docs/monitoring_chassis_pgood.md

1 # Monitoring Chassis Power Good
5 The power sequencer device provides a chassis power good (pgood) signal. This
9 chassis pgood signal from a named GPIO. For more information, see
12 The resulting chassis pgood value is used to set the `pgood` property for the
13 chassis. See [Chassis Status](chassis_status.md) for more information on this
16 If the chassis pgood state is false when it should be true, a chassis power good
20 ## Unable to read chassis power good signal
22 `phosphor-power-sequencer` may become unable to read the chassis power good
27 - The `Available` property of the chassis changes to false.
31 If `phosphor-power-sequencer` is unable to read the chassis power good signal
34 - If this is a single chassis system:
36     read the chassis power good status.
37   - `phosphor-chassis-state-manager` will [power off](powering_off.md) the
39 - If this is a multiple chassis system:
40   - If the chassis is experiencing a blackout:
42   - If the chassis is not experiencing a blackout:
44       read the chassis power good status.
46       inventory path of the chassis to the error log. This may result in
47       hardware isolation, which will cause the `Enabled` property of the chassis
49   - `phosphor-chassis-state-manager` will power the system
50     [off](powering_off.md) and then [on](powering_on.md) again. If the chassis's
51     `Available` or `Enabled` property is false, the chassis will not be powered
56 If `phosphor-power-sequencer` is unable to read the chassis power good signal
57 after the chassis powered on, the application will do the following:
59 - If this is a single chassis system:
60   - Log an error specifying an inability to read the chassis power good status.
63 - If this is a multiple chassis system:
64   - If the chassis is experiencing a blackout:
67     - Power the system off and then on again. If the chassis's `Available`
68       property is false, the chassis will not be powered on.
69   - If the chassis is not experiencing a blackout:
70     - Log an error specifying an inability to read the chassis power good