[SeaBIOS] [PATCH 3/3] acpi: revert d9f5cdbdf (DSDT: Fix HPET _CRS Method)

[Gabriel L. Somlo]

On Fri, Dec 07, 2012 at 10:26:48AM -0500, Gabriel L. Somlo wrote:
> On Fri, Dec 07, 2012 at 10:24:58AM +0100, Gerd Hoffmann wrote:
> > On 12/06/12 21:56, Kevin O'Connor wrote:
> > > On Thu, Dec 06, 2012 at 06:10:46PM +0100, Alexander Graf wrote:
> > >> You should be able to poke fw_cfg in the _STA method. The machine
> > >> file could search its bus on init (or on machine create notify) and
> > >> populate a fw_cfg variable to indicate whether it found an applesmc.
> > > 
> > > I don't think we should access fw_cfg from the AML code.  AML code is
> > > already too fragile and I think accessing fw_cfg is just going to make
> > > it worse.
> > 
> > One can poke at the applesmc directly for detection ...
> 
> We should return 0x0B on success, not 0x0F, though.
> 
> > +        Method(_STA, 0) {
> > +            Store(0x10, CMDP)    // APPLESMC_READ_CMD
> > +            Store(CMDP, Local0)
> > +            If (LEqual(Local0, 0x0c)) {

Also, once you've tickled the CMDP, the SMC internal state is no
longer what OS X expects, so it gets all hung up on that later during
the boot process. I guess I'll put "gain thorough understanding of the
qemu applesmc state machine" on my ToDo list :)

--Gabriel