lockups on lenovo p43s under current

[Pete Wright]

hello,
i have a lenovo thinkpad P43s that exhibits lockups under CURRENT but 
behaves fine when running STABLE.  i've tried to find a fully 
reproducible situation to get this system to lockup but haven't found 
anything yet.  i am starting to suspect that the changes implemented in 
this review may be the issue though:

https://reviews.freebsd.org/D23728

my reasoning is that i've observed issues when:
- removing AC power from the laptop, or inserting AC power
- when the system display has gone to sleep
- randomly hanging during boot with this as last line:
battery0: battery enitialization start

unfortunately while the above seem to be cases where this has happened i 
haven't been able to %100 reproduce yet.

so my first question is - would it be possible to just revert the 
changes in that diff, or has too much time gone past to just back out 
that single change.  alternatively, is there any debugging information i 
can get on my end that might help figure out what the root cause is?

cheers,
-pete

-- 
Pete Wright
pete at nomadlogic.org
@nomadlogicLA