Re: [Qemu-devel] [PATCH 09/11] ACPI: move PRST OperationRegion into SSDT

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 16 Dec 2013 23:22:56 +0100
Laszlo Ersek <lersek@redhat.com> wrote:

> On 12/16/13 22:59, Igor Mammedov wrote:
> > On Mon, 16 Dec 2013 22:44:46 +0100
> > Laszlo Ersek <lersek@redhat.com> wrote:
> > 
> >> On 12/16/13 21:38, Igor Mammedov wrote:
> >>> On Mon, 16 Dec 2013 21:30:14 +0200
> >>> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> >>>
> >>>> On Fri, Dec 13, 2013 at 05:22:14PM +0100, Igor Mammedov wrote:
> >>>>> .. and report range used by it to OSPM via _CRS.
> >>>>> PRST is needed in SSDT since its base will depend on
> >>>>> chipset and will be dynamically set by QEMU.
> >>>>> Also move PRSC() method along with PRST since cross
> >>>>> table reference to PRST doesn't work.
> >>>>
> >>>> Could you clarify this last sentence?
> >>>> I don't mind where it is but I'd like to know
> >>>> where does the limitation come from.
> >>> It's empiric deduction so far I haven't found such limitation in spec yet.
> >>> iasl builds tables just fine but neither linux nor windows were able to find
> >>> Operation region from SSDT when loading DSDT, failing whole table loading
> >>> process. Decompiling DSDT/SSDT tables in guest shows that region is in
> >>> expected scope but OSPM refuses to see it when referenced outside SSDT.
> >>> Maybe there is some AML magic to make it work, I'm not aware of.
> >>> The same thing I had to do for memory hotplug as well. So I've tried to play
> >>> nicely 2 times and I have ended up with this solution both times.
> >>
> >> Would this work?
> >>
> >> diff --git a/hw/i386/acpi-dsdt-cpu-hotplug.dsl b/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> >> index 995b415..34fad66 100644
> >> --- a/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> >> +++ b/hw/i386/acpi-dsdt-cpu-hotplug.dsl
> >> @@ -52,8 +52,8 @@ Scope(\_SB) {
> >>          Sleep(200)
> >>      }
> >>  
> >> -    OperationRegion(PRST, SystemIO, 0xaf00, 32)
> >> -    Field(PRST, ByteAcc, NoLock, Preserve) {
> >> +    External(\_SB.CPHD.PRST, OpRegionObj)
> >> +    Field(\_SB.CPHD.PRST, ByteAcc, NoLock, Preserve) {
> > that was my first patch attempt :)
> > You have to be careful and touch [q35-]acpi-dsdt.dsl since make doesn't
> > handle deps to acpi-dsdt-cpu-hotplug.dsl correctly.
> 
> Yeah I think I noticed from the "make" output :) I grepped it for this
> file's name.
> 
> > After that RHEL6 guest fails to load ACPI tables.
> 
> Could even be an ACPICA problem...
Maybe it's iasl issue or linux&windows implementation is wrong (unlikely).

> 
> Thanks!
> Laszlo
> 
> 


-- 
Regards,
  Igor