[Skiboot] [PATCH] phb4: Avoid complete reset without finishing slot polling

Stewart Smith stewart at linux.vnet.ibm.com
Fri Sep 15 17:34:19 AEST 2017

Russell Currey <ruscur at russell.cc> writes:
> On Fri, 2017-09-15 at 17:02 +1000, Stewart Smith wrote:
>> Russell Currey <ruscur at russell.cc> writes:
>> > In rare circumstances, a complete reset can be requested on a slot while
>> > it is still going through the link polling process.  This results in the
>> > link never coming up.  In complete reset, check to see if the link needs
>> > to complete its state transitions, and if so poll to completion.
>> I was having a bit of a problem with this on my (DD1) zz. I naturally
>> saved all the logs and spent a whole bunch of time debugging. No,
>> wait, that would have been all useful or something.
>> Instead, I went "err... stopped in PCI in kernel, let's randomly pull this
>> patch out to see if it fixes it"... and then it booted.
>> Any ideas? Want to borrow the system to tell me I just saw something
>> random and rather that your code is perfect?
> Sounds good.  This patch has been tested quite a bit and seems to be doing more
> fixing than breaking, maybe there's some weird case on DD1

or zz. or my zz. Or the random old FSP build that's on my zz. All the
things that could be wrong with prerelease hardware could well be wrong here.

Stewart Smith
OPAL Architect, IBM.

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