phosphor-power-sequencer/docs/multiple_chassis.md

5 A BMC-based system can contain one or more chassis. A chassis is typically a
6 physical enclosure that contains system components such as CPUs, fans, power
9 A chassis can be stand-alone, such as a tower or desktop. A chassis can also be
12 For the `phosphor-power-sequencer` application, the term "single chassis system"
19 ### System and chassis power state
21 In a single chassis system, the system and chassis power state are identical.
22 Both are either on or off.
24 In a multiple chassis system, each chassis has its own power state. Even if the
25 system is on, an individual chassis may be off. This can occur if that chassis
26 does not have input power or has a critical hardware problem.
30 ### Chassis power good faults
32 If a single chassis system experiences a power good (pgood) fault, the system is
35 If a multiple chassis system experiences a power good (pgood) fault in one
36 chassis, the system will be powered off and then powered on again without that
39 See [Power Good Faults](pgood_faults.md) for more information.
43 If a single chassis system that was powered on experiences a brownout, the
46 If a multiple chassis system that was powered on experiences a brownout in one
47 chassis, the system will be powered off and then powered on again without that
50 See [Power Loss](power_loss.md) for more information.
54 If a single chassis system that was powered on experiences a blackout, the
55 system loses all power. It will be completely off until utility power is
56 restored. It may then automatically power on again depending on the Auto Power
59 If a multiple chassis system that was powered on experiences a blackout in one
60 chassis, that chassis loses all power. The system will be powered off and then
61 powered on again without that chassis.
63 See [Power Loss](power_loss.md) for more information.