Re: [Qemu-arm] [Qemu-devel] [PATCH v3 1/8] hw/arm/virt: Add a GPIO controller

[Shannon Zhao <shannon.zhao@linaro.org>]

On 2015/12/1 22:48, Pavel Fedin wrote:
>   Hello!
>
>>>> ACPI 5.0 supports GPIO-signaled ACPI Events. This can be used for
>>>> powerdown, hotplug evnets. Add a GPIO controller in machine virt,
>>> s/evnets/events/
>>>
>>>> to support powerdown, maybe can be used for cpu hotplug. And
>>>> here we use pl061.
>
>   Sorry for late jumping in, but this was the first message Cc'ed to me.
>   With these devices virt machine IMHO goes farther and farther away from its initial goal: be a minimalistic virtual box, which ensures maximum possible compatibility and portability.
>   virt machine already supports poweroff using PSCI interface. Why we need to add more hardware? Can't ACPI deal with PSCI?
Hi Pavel,

IIUC, the poweroff using PSCI interface is the guest *internal* 
poweroff, that is you type "poweroff" inside guest. But this patch set 
is going to introduce a way to support *external* poweroff, like the 
power button on our desktop. This is something like you push a button to 
shutdown the guest.

>   To tell the truth, i dislike ACPI + EFI thing at all. It looks like cramming PC-oriented firmware into architecture for which it was never meant to be written. Too much overcomplications, we drop already established things and reinvent a (triangular) wheel, but what's the purpose? Is it being done only because vendors want obscure proprietary firmware instead of old good u-boot?
>
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
>

-- 
Shannon