Adding dependent service as Entity-manager to Ipmb-fru-service

[Ed Tanous]

On Mon, Jun 21, 2021 at 2:28 AM Kumar Thangavel <thangavel.k at hcl.com> wrote:

> Classification: *Confidential*
>
> Hi All,
>
>
>
>            Ipmb-fru-device deamon trying to read some dbus objects from
> entity-manager to get the ipmb bus details. Entity-manager daemon initially
> taking some time to load all the dbus objects. But Ipmb-fru-device deamon
> starts at system startup.
>
>
>
>            Since, Entity-manager deamon initially taking some time to load
> all the dbus objects, ipmb-fru-device getting the below error.
>
>
>
>           *Error* :
>
>           “ipmb-fru-device[345]:   what():  sd_bus_call:
> org.freedesktop.DBus.Error.UnknownObject: Unknown object
> '/xyz/openbmc_project/inventory/system/board/Yosemite_V2_Baseboard/IpmbBus1'.”
>

The easiest way to explain this would be to just point you at code.  Every
dbus-sensor daemon handles this race condition;  I'd recommend looking at
the code in the relevant main(), and see how it does it.  If you have
trouble understanding it, feel free to message back here with specific line
numbers and questions and we should hopefully be able to get you sorted out.


>
>
>          When we restart EM deamon once, this error got resolved.
>
>
>
>          I tried to add EM service as dependent service to Ipmb-fru-device
> service. Added EM service in “Wants”, “After” fields in Ipmb-fru-service
> service.
>
>
>
>          But, still EM deamon taking some time load all the dbus objects.
>

This is intentional.  Because of the way hardware gets detected, new
devices or different configurations could be loaded at any time.  Some
devices aren't detected until the host OS boots for example, so we can't
hold the service startup to wait for the entire system to be detected.


>
>
>          So, Could you please let us know to how to add the EM as
> dependent service. Or Please let us know if any other approach.
>
>
>
> Thanks,
>
> Kumar.
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