Re: [kvm-devel] [PATCH 2/5] SCI fixes (v2)

[Anthony Liguori <aliguori@us.ibm.com>]

Alex Williamson wrote:
> On Mon, 2008-02-04 at 09:11 -0600, Anthony Liguori wrote:
>   
>> @@ -97,11 +100,12 @@ static void pm_update_sci(PIIX4PMState *s)
>>      pmsts = get_pmsts(s);
>>      sci_level = (((pmsts & s->pmen) &
>>                    (RTC_EN | PWRBTN_EN | GBL_EN | TMROF_EN)) != 0);
>> -    qemu_set_irq(s->dev.irq[0], sci_level);
>> +    qemu_set_irq(s->irq, sci_level);
>>      /* schedule a timer interruption if needed */
>>      if ((s->pmen & TMROF_EN) && !(pmsts & TMROF_EN)) {
>>          expire_time = muldiv64(s->tmr_overflow_time, ticks_per_sec, PM_FREQ);
>>          qemu_mod_timer(s->tmr_timer, expire_time);
>> +        s->tmr_overflow_time += 0x800000;
>>     
>
> Hi Anthony,
>
> I'm digging up a patch from a while back.  What's the purpose of bumping
> tmr_overflow_time here?  It seems like this is intended to prevent the
> timer overflow status from ever triggering an SCI, but that seems
> contrary to the ACPI spec.  I've tracked down a case where Vista is
> enabling the timer overflow and appears to get stuck if it never gets
> the overflow interrupt.  Commenting out the last line here fixes it.
> Suggestions?  Thanks,
>   

Avi is the original author of the patch I believe.  Perhaps he can shed 
some light on this?

Regards,

Anthony Liguori

> 	Alex
>
>