Re: [Qemu-devel] [PATCH]Fix a error in mc146818rtc.c

[Lb peace]

1)“ it's an automated output of perl simply changing one calling convention to another”.What do you mean... I 

can not find the point :)

2) The problem is :

      a.use QEMU to run linux-0.2.img with command qemu-system-i386 linux-0.2.img or sth. like that

      b.hwclock ,and we get a date1(2014-07-01 12:00,e.g.)

      c.change the clock of host before date1(2014-04-01 12:00),called date2

      d.hwclock,and we get another date3(2014-07-01,12:01)

      e. before that patch date3 is synchronized with host,so it changed to a time   date3>date2 && date3<date1

          after that patch  date3 is not synchronized with host.It has its own clock,so date3 >date1

3)why we set a reset_notifiers of QEMU_CLOCK_REALTIME? Any comment to that? A QEMU_CLOCK_REALTIME clock will 

 not call its  reset_notifiers when the time is adjusted to a time-point before.The reset_notifiers is useless for this type of QEMUClock.

2014-07-01 4:08 GMT+08:00 Alex Bligh <address@hidden>:

On 30 Jun 2014, at 20:53, Lb peace <address@hidden> wrote:

> If you use hwclock in guest os ,you will find the result of hwclock isn't changed after changing host os's clock.
> I find this issue is generated in this patch:

I find it hard to believe that the patch you mention is the problem,
as it's an automated output of perl simply changing one calling
convention to another.

Is this because you are using an unusual clock= option?

Alex

> http://lists.gnu.org/archive/html/qemu-devel/2013-08/msg03353.html
> Before this patch,the result will be changed if you change host's clock.
> It makes use of the following codes in qemu-timer.c:
>         if (now < last) {
>             notifier_list_notify(&clock->reset_notifiers, &now);
>         }
> It is useless if you register a QEMU_CLOCK_REALTIME's clock_reset_notifier,
> ---
>  hw/timer/mc146818rtc.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
> index df54546..821c27e 100644
> --- a/hw/timer/mc146818rtc.c
> +++ b/hw/timer/mc146818rtc.c
> @@ -879,7 +879,7 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
>      check_update_timer(s);
>
>      s->clock_reset_notifier.notify = rtc_notify_clock_reset;
> -    qemu_clock_register_reset_notifier(QEMU_CLOCK_REALTIME,
> +    qemu_clock_register_reset_notifier(rtc_clock,
>                                         &s->clock_reset_notifier);
>
>      s->suspend_notifier.notify = rtc_notify_suspend;
> --
>

--
Alex Bligh