[Bug 59321] S4 broken with Haswell

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=59321

--- Comment #21 from Takashi Iwai <tiwai at suse.de> ---
(In reply to Paulo Zanoni from comment #20)
> Hi
> 
> I did some more investigation and I discovered the following:
> 
> - It seems that, after resuming, if you run "slabinfo -v" (from tools/vm/),
> there's a good chance you'll see dmesg messages saying we detected
> corruption on our slabs. It seems to me that it is much much easier to
> reproduce the bug with "hibernate, resume, run slabinfo -v, check dmesg,
> hibernate, resume, etc" than with just "hibernate, resume". Can you confirm
> that?

I have no time in this week due to company's event, but I guess this would
trigger more often, too.  In my tests, an easy way to reproduce the bug is to
run netconsole in background on the Haswell machine.  Then it causes after just
a couple of S4 cycles.

> - It also seems that the bug goes away if the kernel that resumes the
> machine doesn't load i915.ko. So an experiment you can try is: boot the
> machine normally, with i915.ko loaded, tell it to hibernate. Then make the
> machine wake-up, and use the "modprobe.blacklist=i915" option when loading
> the kernel that will resume the machine. After it resumes, check if the bug
> is there (possibly with slabinfo -v). The bug should be gone. Can you please
> confirm that?

This was already mentioned in the bug description!

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