Return Task / Don't return until NTP stops

[gtmills]

Return a Task or don't return until NTP has stopped so the GUI doesn't have to have a 20 second timeout

When time mode is initially set to Manual from NTP,
NTP service is disabled and the NTP service is
stopping but not stopped, setting time will return an error.
There are no responses from backend to notify when NTP is stopped.

Date-time bug openbmc/openbmc#3459
https://ibm-systems-power.slack.com/archives/C0Q6TQP5Z/p1616420134178500

Looking to get rid of the 20 sec timeout on the GUI here:
https://github.com/openbmc/webui-vue/blob/master/src/store/modules/Settings/DateTimeStore.js#L49

To do that need to not return until NTP stops or return a task the client (GUI) can watch

I suspect we need some changes here: https://github.com/openbmc/phosphor-time-manager

[lxwinspur]

@gtmills @mzipse

review by:
https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56581
https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56582
https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56583
https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56584

[lxwinspur]

@gtmills @mzipse

Regarding this issue, I pushed a new patch: https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56584
And Looks like the maintiner is against adding this feature to the timeManager repo, because he think that this logic should be handled where it is called.
But we still did some refactoring to the timeManager repo。

So, What do you think?

[gtmills]

We discussed this in discord, are you planning anything here @lxwinspur ?

[lxwinspur]

We discussed this in discord, are you planning anything here @lxwinspur ?

I pushed a commit for this issue: https://gerrit.openbmc.org/c/openbmc/phosphor-time-manager/+/56584
But Lei disagreed with this patch, do you have any suggestions? Do we need to change systemd?