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

[Stewart Smith]

Russell Currey <ruscur at russell.cc> writes:
> On Fri, 2017-09-15 at 17:34 +1000, Stewart Smith wrote:
>> 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.
>> 
>
> Not sure if it's your issue or not, but there are some known problems with this
> patch so hold off on merging, I'll respin once I figure it out.
>
> Or merge it anyway.  The overall level of broken probably won't change much.

Any further thoughts?

-- 
Stewart Smith
OPAL Architect, IBM.