Re: [Qemu-devel] [PATCH 3/3] Get system state configuration from QEMU and patch DSDT with it.

[Avi Kivity]

On 05/20/2012 03:15 PM, Gleb Natapov wrote:
> On Sun, May 20, 2012 at 02:44:51PM +0300, Avi Kivity wrote:
> > On 05/20/2012 12:03 PM, Gleb Natapov wrote:
> > > QEMU may want to disable guest's S3/S4 support and it wants to distinguish
> > > between regular powerdown and S4 powerdown. To support that new fw_cfg
> > > option was added that passes supported system states and what value should
> > > guest use to enter each state. States are passed in 6 byte array. Each
> > > byte represents one system state. If byte at offset X has its MSB set
> > > it means that system state X is supported and to enter it guest should
> > > use the value from lowest 7 bits. Patch also detects old QEMU and uses
> > > values that work in backwards compatible way there.
> > >
> > 
> > 
> > Do we actually have to patch the DSDT?  Or can _S3 etc be made into
> > functions instead? (and talk to the bios, or even to fwcfg directly?)
> > 
> We better not talk to fwcfg after OSPM is started since this is firmware
> confing interface.

Why not?  The OS isn't going to talk to it, so we can have a driver in ACPI.

>  Regardless, presence of _S3 name or method is all
> that needed for OS enabling S3 option. If _S3 is defined as a method it
> has to return Package() otherwise iasl refuses to compile it.

Can't we Return (Package (...) { ... }) or equivalent? 

-- 
error compiling committee.c: too many arguments to function