Request for Feedback :: Time Mode setting in timemanager

Brad Bishop bradleyb at
Wed Feb 19 01:40:53 AEDT 2020

> On Feb 18, 2020, at 7:56 AM, Vishwanatha Subbanna <vishwa at> wrote:
> Hello,
> Sending this email requesting feedback on one of the feature that we currently have in phosphor-timemanager.
> Time manager uses TimeMode setting and can have either [NTP] or [Manual] as the valid options and are provided via xyz/openbmc_projects/settings/ for external users.
> When the system power is off and BMC is in ready state, any changes to these settings are readily consumed by time manager daemon.
> However, if the user changes the setting when the Host is booting, timemanager puts them in deferred state. Meaning, timemanager does not take the settings into effect until the Host is powered off.

Can you elaborate on why it does this?

> So, if someone wants to move from [Manual] to [NTP] or vice-versa, when the Host is [On], they need to [power-off] the Host and power it back on.

This seems less than ideal?  Would you agree?

> This design was chosen because we wanted to give priority to Host.

What does it mean to give priority to the Host?  Are you trying to hide time changes in the time from the host?  Why?

> Some of us are asking me if we can make a change to take the setting changes in effect immediately, not caring the state of the Host.

Without additional background this is what seems intuitive to me.

> Please could you help with your thoughts on this ?.. What is the Industry norm on this ?

FWIW on our (IBM) system designs we usually hook an RTC up to the BMC, and any host software needing a RTC has to get it via some in-band software interface.  I think I heard somewhere though that often in other systems designs the RTC is connected to the host processors and the BMC doesn’t have access to it.

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