[Skiboot] [PATCH v2 1/9] core/pci: Return error on invalid power state transition

[Andrew Donnellan]

On 13/10/16 15:29, Gavin Shan wrote:
> On Thu, Oct 13, 2016 at 03:18:10PM +1100, Andrew Donnellan wrote:
>> On 13/10/16 12:16, Gavin Shan wrote:
>>> This returns error (OPAL_PARAMETER) when having invalid power state
>>> transition requests. The invalid requests include: ON to ON, OFF to
>>> OFF.
>>>
>>> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>>
>> What's the advantage of doing this rather than immediately returning
>> OPAL_SUCCESS?
>>
>
> There are two purposes: (1) To notify the caller the invalid power state
> switching; (2) After this patchset is applied, OPAL_SUCCESS will causes
> an PCI topology update, which is totally unecessary if we don't have
> power (hotplug) state change. This is required by surprise hotplug that
> relies on interrupts caused by link up/down events, meaning we cannot
> put the slot into power-off state under the situation.

OK.

Reviewed-by: Andrew Donnellan <andrew.donnellan at au1.ibm.com>


-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited