Re: 2.6.21rc suspend to ram regression on Lenovo X60

[Matt Mackall <mpm@selenic.com>]

On Tue, Mar 13, 2007 at 12:08:28AM -0400, Dave Jones wrote:
> I spent considerable time over the last day or so bisecting to
> find out why an X60 stopped resuming somewhen between 2.6.20 and current -git.
> (Total lockup, black screen of death).
> 
> The bisect log looked like this.
> 
...
> Any ideas how to further debug this?
> I'll try backing out individual changes from that merge tomorrow.

If you've got a tree that looks like:

 --a-b-c-d-e-f-g-h->
    \           /
     i-j-k-l-m-n

where h is bad but both g and n are good, you can try testing the
merge of g+k, etc. Which will find half the problem. Then you can do
the same on the other side. Tedious.

The best way to debug resume issues directly seems to be to do a fake
suspend, possibly with filtering out particular devices:

http://lwn.net/Articles/219033/
http://www.uwsg.iu.edu/hypermail/linux/kernel/0701.3/0397.html

-- 
Mathematics is the supreme nostalgia of our time.