Request for Feedback :: Time Mode setting in timemanager

Ryan Arnell ryan1arnell at
Wed Feb 19 03:46:22 AEDT 2020

Thanks Brad and Vishwa for moving into the direction where we might not
require a reboot or host power off from moving to Manual to NTP or vise
We had a lot of user feedback who see this as a very inefficient task.
Goldman and David cc'ed here can also has a lot of customers who needs to
sync time often and they would not like to power off host every time that

Thanks again

On Tue, Feb 18, 2020 at 8:43 AM Brad Bishop <bradleyb at>

> > 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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