Re: [Xen-devel] Time Skewing on Windows XP

[Suravee Suthikulanit <suravee.suthikulpanit@xxxxxxx>]

On 3/14/2013 11:34 AM, Jan Beulich wrote:
> > > > On 14.03.13 at 17:21, Suravee Suthikulanit <suravee.suthikulpanit@xxxxxxx> 
> > > > wrote:
> > On 3/14/2013 11:06 AM, Jan Beulich wrote:
> > > > > > On 14.03.13 at 16:16, Suravee Suthikulanit<suravee.suthikulpanit@xxxxxxx> wrote:
> > > > I finally traced the issue back to the patch that this first happened.  This
> > > > bug started in the patch :
> > > >
> > > > H86/HVM: assorted RTC emulation adjustment (w/ git commit id
> > > > 620d5dad54008e40798c4a0c4322aef274c36fa3)
> > > >
> > > > I believe there are some issues with the changes in rtc_ioport_read in the
> > > > arch/x86/hvm/rtc.c and in the pt_update_irq().
> > > One thing you may want to try is remove the call from REG_C
> > > read to rtc_timer_update() again - on a second thought it may
> > > be wrong to do it here, as (other than check_update_timer()
> > > and alarm_timer_update()) the function doesn't change with
> > > RTC_PF getting cleared (i.e. I may have wrongly added the call
> > > in analogy to the other two).
> > If I do the followings, things start working again:
> > 1. remove the rtc_timer_update() in the rtc_ioport_read()
> > 2. Revert back the "rtc_periodic_cb()" and remove the
> > "rtc_periodic_interrupt()"
> >
> > What was the purpose of changing the "rtc_periodic_cb()" to
> > "rtc_periodic_interrupt()" ?
> The main point was to be able to call rtc_toggle_irq() from that
> function (to get RTC_IRQF properly set), instead of
> pt_update_irq() doing only the IRQ deassert/assert pair.
>
> So removing just the questionable call to rtc_timer_update()
> doesn't help?
>
> Jan
Removing just the call to "rtc_timer_update" causes XP failed to boot 
and hanged.  It seems like it did not get the right timer interrupt it 
was looking for.
Suravee
>


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