Re: [Qemu-devel] [PATCH v3 5/7] RTC:Add RTC update-ended interrupt support

[Zhang, Yang Z]

> -----Original Message-----
> From: Paolo Bonzini [mailto:address@hidden On Behalf Of Paolo
> Bonzini
> Sent: Friday, March 02, 2012 8:14 PM
> To: Zhang, Yang Z
> Cc: address@hidden; Jan Kiszka; address@hidden;
> address@hidden; Marcelo Tosatti
> Subject: Re: [PATCH v3 5/7] RTC:Add RTC update-ended interrupt support
> 
> Il 02/03/2012 08:00, Zhang, Yang Z ha scritto:
> > Use a timer to emulate update cycle. When update cycle ended and UIE
> > is setting, then raise an interrupt. The timer runs only when UF or AF is 
> > cleared.
> 
> Isn't AF=0 the common case when the RTC starts, so the timer always runs until
> the time crosses midnight?

Right. But for server platform, the guest will run always. One day is not a big 
cost. 
And if guest not use the alarm. Then the timer will never run again.
Also, I can set the default value in alarm to 'don't care' mode. And this will 
avoid the timer always runs.

best regards
yang