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

[Laszlo Ersek]

On 12/16/13 22:59, Igor Mammedov wrote:
> On Mon, 16 Dec 2013 22:44:46 +0100
> Laszlo Ersek <address@hidden> wrote:
> 
>> On 12/16/13 21:38, Igor Mammedov wrote:
>>> On Mon, 16 Dec 2013 21:30:14 +0200
>>> "Michael S. Tsirkin" <address@hidden> 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...

Thanks!
Laszlo