Re: [Qemu-devel] [PATCH RFC 0/6] q35: add acpi pci hotplug support

[Alexander Bezzubikov]

Do we have any surely working scenario of pci-bridge's SHPC usage? Because
first of all I've tried to use SHPC to avoi involving any ACPI code, but it
didn't look functioning even for ordinary pci-bridge, that's why after
talking to Marcel I left SHPC idea.

2017-07-03 16:58 GMT+03:00 Alexander Bezzubikov <address@hidden>:

> Hmm, I've failed to make SHPC (from current master) work on any modern
> Linux guests.
>
> 2017-07-03 15:27 GMT+03:00 Igor Mammedov <address@hidden>:
>
>> On Fri, 30 Jun 2017 10:25:05 +0300
>> Marcel Apfelbaum <address@hidden> wrote:
>>
>> [...]
>> >
>> > So for the modern systems not supporting PCI ACPI hotplug
>> > we don't need pci-bridges anyway, but for the older ones
>> > the ACPI code of the pci-bridge will be loaded into the
>> > ACPI namespace only if a pci-bridge is actually hot-plugged.
>>
>> just note that the set of 'older' guest OSes is limited to
>> one that do not support SHPC (i.e. to EOLed WinXP & co)
>> as for linux and more modern Windows SHPC hotplug should
>> just work without our ACPI hack (which taxes low memory
>> to keep acpi tables for bridges).
>>
>> So I'm in favor of Michael's suggestion to leave ACPI PCI
>> only in PC machine for old WinXP guests and to keep Q35
>> clean, where linux or newer Windows guests could just
>> use standard SHPC.
>>
>> [...]
>>
>
>
>
> --
> Alexander Bezzubikov
>



-- 
Alexander Bezzubikov