Re: [Qemu-devel] [PATCH 0/5] PCI hotplug fixes/cleanup

[Michael S. Tsirkin]

On Tue, Apr 10, 2012 at 12:29:09PM -0600, Alex Williamson wrote:
> I never really intended the power state bitmap to be for power
> management of any sort, I was trying to support this kind of event flow:
> 
> http://www.microsoft.com/china/whdc/system/pnppwr/hotadd/hotplugpci.mspx#EYH
> 
> Hot-add:
>  - Generate SCI
>  - _Lxx/_Exx method determines which slots to Notify
>  - _STA method for slots indicates device present
>  - _PS0 requests slot turned on
>  - _STA method reports device present & enabled
> 
> Hot-remove:
>  - Generate SCI
>  - _Lxx/_Exx method determines which slots to Notify
>  - _PS3 powers off slot
>  - _EJ0 ejects device
>  - _STA verifies success
> 
> _STA is generated using the "present" and "power" registers and _PSx
> methods directly manipulate "power".  We could then have some kind of
> "info pcislot" command that allows querying slot state.  Maybe there's
> even an opportunity for unpowered slot surprise removal.  In effect, the
> "power" register tracks the "actual" state vs the "requested" state, but
> if it's controlled by _PSx, it seems better to not try to do a
> translation.
> 
> Are there better models or event flows we should be aiming for?  Thanks,
> 
> Alex

You already said exactly this and both me and Marcelo responded, no?

-- 
MST