Re: Time Skewing on Windows XP

[Suravee Suthikulanit <suravee.suthikulpanit@amd.com>]

On 3/14/2013 11:34 AM, Jan Beulich wrote:
>>>> On 14.03.13 at 17:21, Suravee Suthikulanit <suravee.suthikulpanit@amd.com> wrote:
>> On 3/14/2013 11:06 AM, Jan Beulich wrote:
>>>>>> On 14.03.13 at 16:16, Suravee Suthikulanit<suravee.suthikulpanit@amd.com> 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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