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. 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.
-- Gleb.