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Re: [Qemu-devel] [PATCH] RTC: enable lost_tick_policy=slew as default (v
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH] RTC: enable lost_tick_policy=slew as default (v2) |
Date: |
Fri, 08 Mar 2013 11:53:38 -0600 |
User-agent: |
Notmuch/0.13.2+93~ged93d79 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Marcelo Tosatti <address@hidden> writes:
> On Thu, Mar 07, 2013 at 09:25:17AM +0100, Paolo Bonzini wrote:
>> Il 12/12/2012 22:36, Marcelo Tosatti ha scritto:
>> >
>> > RTC interrupt reinjection has no known negative effect. Lack of
>> > RTC interrupt reinjection, though, has negative effects: time drift
>> > for Windows guests which use it as a timer source.
>> >
>> > Based on that, enable lost_tick_policy=slew option as default.
>> >
>> > Signed-off-by: Marcelo Tosatti <address@hidden>
>> >
>> > v2: do not change default for older machines types (Paolo Bonzini)
>> >
>> > diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
>> > index c79fca7..c9e007d 100644
>> > --- a/hw/mc146818rtc.c
>> > +++ b/hw/mc146818rtc.c
>> > @@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year,
>> > qemu_irq intercept_irq)
>> > static Property mc146818rtc_properties[] = {
>> > DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
>> > DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
>> > - lost_tick_policy, LOST_TICK_DISCARD),
>> > + lost_tick_policy, LOST_TICK_SLEW),
>> > DEFINE_PROP_END_OF_LIST(),
>> > };
>> >
>> > diff --git a/hw/pc_piix.c b/hw/pc_piix.c
>> > index 19e342a..475bb4c 100644
>> > --- a/hw/pc_piix.c
>> > +++ b/hw/pc_piix.c
>> > @@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
>> > .driver = "usb-tablet",\
>> > .property = "usb_version",\
>> > .value = stringify(1),\
>> > + },{\
>> > + .driver = "mc146818rtc",\
>> > + .property = "lost_tick_policy",\
>> > + .value = "discard",\
>> > }
>> >
>> > static QEMUMachine pc_machine_v1_3 = {
>> >
>> >
>>
>> Looks like this was never applied. Can you redo it for the new 1.5
>> machine (compatibility defines are now in hw/pc.h)?
>>
>> Paolo
>
> Anthony mentioned that this
>
> http://article.gmane.org/gmane.comp.emulators.qemu/160699
>
> Is the proper way to do it.
That breaks too. I don't have a solution but I also don't remember what
the exact failures are.
I'm planning on running this patch through testing again so I can
provide better feedback.
Regards,
Anthony Liguori