[Skiboot] [PATCH] FSP/RTC: Fix possible FSP R/R issue in rtc write path
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.
> 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
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
OPAL Architect, IBM.
More information about the Skiboot