Creating event logs for blackout power losses

[Matt Spinler]

On 7/24/2019 2:53 PM, Bills, Jason M wrote:
> On 6/28/2019 8:26 AM, Matt Spinler wrote:
>> Hi,
>> We've been asked by field support to create an OpenBMC event log when 
>> we detect that
>> we suffered a power blackout, by which I mean the system is up and 
>> running, and then the
>> BMC suddenly reboots and when it comes back up main power is off. The 
>> issue for it is
>> https://github.com/ibm-openbmc/dev/issues/677.
>>
>> I have a proposal in there for how to detect it in the chassis state 
>> manager code, which
>> basically just consists of persisting the chassis power state and 
>> then checking it against
>> the actual value on startup, and an error proposed at
>> https://gerrit.openbmc-project.xyz/c/openbmc/phosphor-dbus-interfaces/+/22791. 
>>
>> Does anyone have any other ideas or thoughts?  Is it OK if we make 
>> this the default behavior, or
>> would it be preferred we enable it with a compile flag?
>
> Sorry for the late replay as I have been out of the office.
>
> In my testing on this type of failure, I found that there is a race 
> condition between the Chassis and BMC losing power after the blackout. 
> If the Chassis loses power while the BMC is still active, it can 
> sometimes detect it, change the Chassis State to Off, and persist it 
> before losing power.  When this happens, the next boot will see only 
> the Off state persisted and not detect the blackout.
>
> To work around this, we have added a delay when persisting the Chassis 
> State.  In a normal Off, it will be persisted after the delay; in a 
> blackout off, the delay will prevent the BMC from persisting the Off 
> state allowing the blackout to be detected.

Hi, thanks for the response.
Did you do this in a downstream phosphor-state-manager repository,
or somewhere else?  If in phosphor-state-manager, would you consider 
sharing it?

>
>>
>> Thanks,
>> Matt
>