docs/designs/bmc-boot-ready.md

1 # BMC Boot Ready
11 There are services which run on the BMC which are required for the BIOS (host
17 been collected from the VRM's by the BMC to determine their characteristics. On
21 Currently, OpenBMC has an undefined behavior in this area. If a particular BMC
22 has a large time gap between when the webserver is available and when all BMC
28 The mailing list discussion can be found [here][1]. The BMC currently has three
29 major [state][2] management interfaces in a system. The BMC, Chassis, and Host.
32 The [BMC][3] state object is considered `Ready` once the systemd
33 `multi-user.target` has successfully started all if its services.
37 1. D-Bus objects don't exist until the backend is prepared to handle them.
43 Option 1 is challenging because D-Bus interfaces provided by OpenBMC state
44 applications have a mix of read-only properties (like current state) and
51 the op-panel code now need to properly handle error codes like this. You can
60 [1]: https://lists.ozlabs.org/pipermail/openbmc/2022-April/030175.html
62   https://github.com/openbmc/phosphor-dbus-interfaces/tree/master/yaml/xyz/openbmc_project/State
64 …https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/yaml/xyz/openbmc_project/State/BMC…
68 - Queue up chassis and host requested state changes until the BMC is in the
70   - What the "proper state" is will be implementation specific but by default
71     phosphor-state-manager will queue all requests until the BMC state has
77 the BMC is not at `Ready` then the request will be queued and the state
78 management code will begin monitoring for BMC `Ready`. Once reached, the
90 multi-user.target and all of it's dependent services have completed prior to a
92 easier and safer to just have a global wait-for-bmc-ready function as proposed
98 delayed by an undefined amount of time. In general, a BMC gets to Ready state
103 This function will be implemented within the existing phosphor-state-manager
104 repository. x86-power-control, an alternative to phosphor-state-manager, could
109 - Ensure a power on request is properly queued and executed when it is made
110   prior to the BMC being `Ready`.