[Skiboot] [PATCH v11 22/23] core/opal: Extend opal_pci_set_power_state()

Stewart Smith stewart at linux.vnet.ibm.com
Wed Jun 8 20:39:02 AEST 2016

Gavin Shan <gwshan at linux.vnet.ibm.com> writes:
> On Wed, Jun 08, 2016 at 05:59:44PM +1000, Andrew Donnellan wrote:
>>On 08/06/16 17:34, Stewart Smith wrote:
>>>I guess the reason that you want to offline then online rather than just
>>>rescan is that you may need to update what's on the card while it's
>>>offline? Except that the card will be offline... so not sure how that
>>>would work?
>>>Why not a RESCAN rather than OFFLINE/ONLINE pair?
>>Right now, I'd be quite happy with a RESCAN rather than OFFLINE/ONLINE - my
>>current cxl driver code is switch-to-CAPI-mode -> OFFLINE -> ONLINE. I think
>>this option was mentioned in our in-person discussions about how this should
>>work. I can't personally think of a usecase where the OFFLINE/ONLINE pair is
>>more useful, though Gavin may have other thoughts there.
> It's all about the granularity we can have. With OFFLINE/ONLINE, more
> granularity is given comparing to RESCAN. EEH potentially offline all
> devices behind a PCI slot upon excessive errors in future. So I think
> OFFLINE/ONLINE seems more reasonable.

That makes sense, OFFLINE/ONLINE it is.

Stewart Smith
OPAL Architect, IBM.

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