Re: [libvirt] [PATCH] Add support for disabling S3 and S4 states

On Mon, Jul 30, 2012 at 02:43:33PM +0200, Martin Kletzander wrote: > On 07/30/2012 02:33 PM, Daniel P. Berrange wrote: >> On Mon, Jul 30, 2012 at 02:25:04PM +0200, Martin Kletzander wrote: >>> There a two new elements in <features> implemented, which control what >>> ACPI sleeping states will be advertised. The default is to have both >>> states enabled, so this means no change for current machines. >> >>> diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng >>> index b7562ad..859cb26 100644 >>> --- a/docs/schemas/domaincommon.rng >>> +++ b/docs/schemas/domaincommon.rng >>> @@ -2788,6 +2788,16 @@ >>> <empty/> >>> </element> >>> </optional> >>> + <optional> >>> + <element name="disable_s3"> >>> + <empty/> >>> + </element> >>> + </optional> >>> + <optional> >>> + <element name="disable_s4"> >>> + <empty/> >>> + </element> >>> + </optional> >>> </interleave> >>> </element> >>> </optional> >> >> This is not very nice design. With this if an app wants to request >> S3, and have an error if it is not supported, they can't do that. >> > > I'm sorry, but I don't quite understand what do you mean. If the guest > wants to go to S3, there is (of course) no difference between the state > not being supported or the support being disabled. If an application > wants to request the guest to go to S3 through libvirt, then it will get > an appropriate message (disabled/not supported). Having one more option > means just setting the QEMU parameter to the default value (0). I'm talking about the host mgmt's POV. An application creating a guest may want to guarantee that S3 is available to the guest. With your proposal, there is no way they can do that - since there is no explicit element in the XML to request S3. So the mgmt app may get a guest with S3, or it may not - it has no way of being sure. The only thing a mgmt app can do is forcably disable S3 .