[Skiboot] [PATCH] FSP/RTC: Fix possible FSP R/R issue in rtc write path

Stewart Smith stewart at linux.vnet.ibm.com
Wed Jun 14 16:56:34 AEST 2017

Vasant Hegde <hegdevasant at linux.vnet.ibm.com> writes:
> On 06/13/2017 03:52 PM, Vasant Hegde wrote:
>> fsp_opal_rtc_write() checks FSP status before queueing message to FSP. But if
>> FSP R/R starts before getting response to queued message then we will continue
>> to return OPAL_BUSY_EVENT to host. In some extreme condition host may
>> experience hang. Once FSP is back we will repost message, get response from FSP
>> and return OPAL_SUCCES to host.
>> This patch caches new values and returns OPAL_SUCCESS if FSP R/R is happening.
>> And once FSP is back we will send cached value to FSP.
> Stewart,
> I missed to add "v2" to subject line. Please consider this patch. Not v1 patch.
> With this changes, OPAL will record new request from kernel  while FSP is in reboot.
> Once FSP is back OPAL will call rtc_flush_cached_tod() to flush the
> data.

Okay, I think this is an okay thing to do in this scenario.

Merged to master as of f4757fbfcf616365c74b1aa6508b2ab27480cdd0

and to 5.4.x as of 79a78d3d8ba61033e6f9084c4519ada1588ebbe1
Stewart Smith
OPAL Architect, IBM.

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