Re: [Xen-devel] HVM Migration of domU on Qemu-upstream DM loses ACPI data in xenstore

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-05-20 at 12:50 +0100, Alex Bligh wrote:
> Ian,
> 
> --On 20 May 2013 09:40:01 +0100 Ian Campbell <Ian.Campbell@xxxxxxxxxx> 
> wrote:
> 
> > You could perhaps verify this somewhat by playing with the kernel's
> > clocksource= option.
> 
> clocksource=[hpet|pit|tsc|acpi_pm|cyclone|scx200_hrt]
> 
> I'm guessing clocksource=tsc is the least dependent on 'other stuff'.

It'd be a good one to start with. You should be able to confirm under
sysfs which one is used now, I'm guessing it is acpi_pm.

It'd be worth trying each of the first 4 though. cyclone and scx200 seem
a bit specific...

> We'll have a play.
> 
> >> Any ideas on how to debug this further? It is odd that the date command
> >> (used to set a date) will unstick the clock.
> >
> > I'd have thought that would only poke the RTC, but to be honest I'm not
> > sure.
> 
> I'm pretty sure date itself only changes the wallclock (the clock command
> normally being needed to write to the RTC).

Yes, I think you are right.

>  If the images are running
> ntp, that may notice the wallclock change and write to CMOS I guess.




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