phosphor-power-sequencer/docs/chassis_status.md

5 There are multiple D-Bus interfaces and properties that describe the chassis
6 status. The `phosphor-power-sequencer` application publishes one of those
7 interfaces. The other interfaces are published by different applications and are
12 The `state` and `pgood` properties exist on the `org.openbmc.control.Power`
15 `state` has a value of 0 or 1. `state` represents the desired power state for
16 the chassis. 0 means off, and 1 means on. This property is set when the system
19 `pgood` has a value of 0 or 1. `pgood` represents the power good (pgood) state
20 of the chassis. 0 means off, and 1 means on. This is the actual, current power
21 state. This property is set based on the chassis power good signal from the
24 `phosphor-power-sequencer` publishes the `org.openbmc.control.Power` interface
25 on the following object paths:
27 - `/org/openbmc/control/power0`: Represents the entire system
35 On a single chassis system, only the first two object paths are published,
36 representing the entire system and chassis 1. The values of the `state` and
39 When the system is powered off, the `state` and `pgood` properties for both
42 When the system is being powered on, the `state` property of both object paths
43 is set to 1. When the chassis has successfully powered on, the `pgood` property
46 When the system is being powered off, the `state` property of both object paths
47 is set to 0. When the chassis has successfully powered off, the `pgood` property
52 On a multiple chassis system with N chassis, all of the object paths above are
53 published. The first object path represents the state of the entire system, and
54 the other object paths represent the state of the individual chassis.
56 When the system is powered off, the `state` and `pgood` properties for all of
57 the object paths are 0.
59 When the system is being powered on, the `state` will be changed to 1 for the
64 When an individual chassis has successfully powered on, the `pgood` property for
66 have successfully powered on, the `pgood` property for the system object path
69 If a power good fault occurs in a chassis after the system powered on, the
70 `pgood` property for that chassis's object path will change to 0. The `pgood`
71 property for the system object path will remain set to 1 for a period of time.
72 Eventually the system will be powered off due to the power good fault. See
75 When the system is being powered off, the `state` will be changed to 0 for the
78 When an individual chassis has successfully powered off, the `pgood` property
80 powered off, the `pgood` property for the system object path will change to 0.
85 the `state` and `pgood` properties. This occurs when a system first receives
86 input power or after the BMC is reset.
88 The chassis power good signal is read from the power sequencer device. Both the
89 `state` and `pgood` properties are set to the value of the power good signal.
90 For example, if the chassis power good is true, both `state` and `pgood` are set
91 to the value 1. Thus, `phosphor-power-sequencer` assumes the chassis `state`
92 based on the chassis `pgood`.
94 In a multiple chassis system, it might not be possible to read the chassis power
95 good signal. For example, the chassis might not be present or might have no
96 input power. See the sections below for information about how the `pgood`
101 The `Present` property exists in the [`xyz.openbmc_project.Inventory.Item`][1]
104 This interface is published on the D-Bus inventory path for each chassis.
105 `phosphor-power-sequencer` does not publish this interface, but it checks the
108 The `Present` property indicates whether a chassis is physically present.
112 - The chassis power good signal from the power sequencer will **not** be read.
113   Since the chassis is not present, the `pgood` property on the
114   `org.openbmc.control.Power` interface for the chassis will be set to 0.
115 - The chassis will **not** be powered on when the system is being powered on.
116   The `state` property on the `org.openbmc.control.Power` interface for the
121 The `Available` property exists in the
124 This interface is published on the D-Bus inventory path for each chassis.
125 `phosphor-power-sequencer` does not publish this interface, but it checks the
128 This interface is optional. If the interface exists and `Available` is set to
129 false, it means that communication to the chassis is not possible. For example,
130 the chassis does not have any input power ([blackout](power_loss.md)) or
131 communication cables to the BMC are disconnected.
135 - The chassis power good signal from the power sequencer will **not** be read.
136   Since communication to the chassis is not possible, the value of the power
137   good signal is unknown. The following algorithm is used to set the value:
138   - If the chassis is experiencing a blackout, the chassis has no input power
140   - If all other chassis have a `pgood` value of 0, the `pgood` value will be
142   - If at least one other chassis has a `pgood` value of 1, the `pgood` value
144 - The chassis will **not** be powered on when the system is being powered on.
145   The `state` property on the `org.openbmc.control.Power` interface for the
150 The `Enabled` property exists in the [`xyz.openbmc_project.Object.Enable`][3]
153 This interface is published on the D-Bus inventory path for each chassis.
154 `phosphor-power-sequencer` does not publish this interface, but it checks the
157 This interface is optional. If the interface exists and `Enabled` is set to
158 false, it means that the chassis has been put in hardware isolation (guarded). A
159 critical error has been detected in the chassis, and it will not be used when
160 the system is powered on.
164 - The chassis power good signal from the power sequencer will be read. The
165   `pgood` property on the `org.openbmc.control.Power` interface for the chassis
166   will be set to the value of this signal.
167 - The chassis will **not** be powered on when the system is being powered on.
168   The `state` property on the `org.openbmc.control.Power` interface for the
173 The `Status` property exists in the
176 `phosphor-power-sequencer` does not publish this interface, but it checks the
179 This interface is optional. If the interface exists and `Status` is set to
180 `Fault`, it means that the chassis is experiencing a blackout or brownout. A
182 failure or an unplugged power cord. See the sub-sections below for more
187 The `phosphor-chassis-power` application publishes the
188 `xyz.openbmc_project.State.Decorator.PowerSystemInputs` interface on the
198 - The chassis is experiencing a blackout.
199 - The chassis power good signal from the power sequencer will **not** be read.
200   Since the chassis has no input power, the `pgood` property on the
201   `org.openbmc.control.Power` interface for the chassis will be set to 0.
202 - The chassis will **not** be powered on when the system is being powered on.
203   The `state` property on the `org.openbmc.control.Power` interface for the
204   chassis will remain set to 0. An error will be logged indicating that the
209 The `phosphor-power-supply` application publishes the
210 `xyz.openbmc_project.State.Decorator.PowerSystemInputs` interface on the
218 If `Status` is set to `Fault` for the PSUs in a chassis:
220 - The chassis is experiencing a brownout.
221 - The chassis power good signal from the power sequencer will be read. The
222   `pgood` property on the `org.openbmc.control.Power` interface for the chassis
223   will be set to the value of this signal.
224 - The chassis will **not** be powered on when the system is being powered on.
225   The `state` property on the `org.openbmc.control.Power` interface for the
226   chassis will remain set to 0. An error will be logged indicating that the