On 10/30/2012 01:10 AM, Rafael J. Wysocki wrote:

On Sunday, October 28, 2012 12:59:49 PM Linus Torvalds wrote:

quoted

It's been a week, time for -rc3!

Nothing particularly stands out here. Lots of small fixes, exemplified
by the series of memory leak fixes in usb serial drivers. Just a lot
of random stuff..

Most of it is drivers (all over: drm, wireless, staging, usb, sound),
but there's a few filesystem updates (nfs, btrfs, ext4), arch updates
(arm, x86 and m68k) and just random stuff. Shortlog appended.

Unfortunately, s2disk is broken with this one and previous -rc.  In the
majority of cases it just hangs the machine during hibernation, although
sometimes it returns to user space reporting freezing problems, suspicions
RCU usage and similar stuff, pretty much without any useful debug information.

I'm quite confident that v3.6 was OK (and -stable based on that too), so
it most likely is a recent regression.  The in-kernel hibernation
(ie. "echo disk > /sys/power/state") works no problem.  So does suspend to
RAM on my test boxes.

Since v3.7-rc1 I am seeing suspend to RAM fail as well. It was obscured 
by a nouveau recursive locking issue on my machine. I reverted the 3.7 
DRM merged completely. From there "echo mem > /sys/power/state" works, 
but choosing suspend like most mere mortals do results in suspend, but 
attempt to resume brings me straight to the BIOS starting anew.

So far I have been able to reproduce this 100% of the time on two machines
with Intel CPUs and graphics driven by i915.  I _suspect_ that this may be
related to VT switching, because s2disk does some ugly things in that area
which are not done by the in-kernel code.  Dunno.

Anyway, it looks like nothing short of bisection is going to help debug this,
but I'm afraid I won't have the time to bisect within the next two weeks, so if
anyone can reproduce this issue and will be able to bisect it, please help
(openSUSE/Tumbleweed users anyone?).

Thanks,
Rafael

Not sure if it has the same root cause. Since DRM revert did not work 
for me I put my money on ACPI (not a lot of money though ;-) ).

Gr. AvS