Re: [Qemu-devel] [PATCH v2] qga: Don't require 'time' argument in guest-set-time command

[Eric Blake]

On 01/31/2014 03:29 AM, Michal Privoznik wrote:
> As the description to the guest-set-time states, the command is
> there to ease time synchronization after resume. If guest was
> suspended for longer period of time, its system time can go off
> so badly, that even NTP refuses to set it. That's why the command
> was invented: to give users chance to set the time (not
> necessarily 100% correct). However, there's is no real need for
> us to require users to pass an arbitrary time. Especially if we
> can read the correct value from RTC (boiling down to reading
> host's time). Hence this commit enables logic:
> 
> guest-set-time() == guest-set-time($now_from_rtc)
> 
> Signed-off-by: Michal Privoznik <address@hidden>
> ---
> diff to v1:
> -Fix checkpatch.pl warnings 
> 
>  qga/commands-posix.c | 41 +++++++++++++++++++++++++----------------
>  qga/commands-win32.c | 34 +++++++++++++++++++++++-----------
>  qga/qapi-schema.json |  9 +++++----
>  3 files changed, 53 insertions(+), 31 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

Conversion from mandatory to optional is backward-compatible.  I'm not
sure if it worth some sort of annotation when it was made optional; maybe:

# @time: (#optional since 2.0) time of nanoseconds, relative to the
#        Epoch of 1970-01-01 in UTC.

we don't have much precedent for that sort of change, but documenting it
may make it more obvious to a user that older agents require an argument.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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