On Monday, August 02, 2010, Stephan Diestelhorst wrote:

On Wednesday 28 July 2010, 23:50:09 Rafael J. Wysocki wrote:

quoted

On Saturday, July 10, 2010, Tejun Heo wrote:

quoted

On 07/10/2010 08:50 AM, Stephan Diestelhorst wrote:

quoted

quoted

I have a box where this problem is kind of reproducible, but it happens _very_
rarely.  Also I can't reproduce it on demand running suspend-resume in a tight
loop.  Are you able to reproduce it more regurarly?

For me it is much more reproducible. If I run multiple direct writing
dd-s to the disk in question I trigger it rather reliably (~75% or
higher). See the attached script from an earlier email.
Maybe that helps triggering your case more reliabl, too?

That didn't help, but the appended patch fixes the problem for me.

<snip>

Sorry for taking ages. Vacation and catching up after it are to blame,
as is me forgetting to build a proper initrd...

Thanks for the patch! It certainly changes behaviour, however, in a
very strange way for me. With your patch my machine does not suspend
to ram anymore (a simple echo mem > /proc/sys/state blocks), and
nothing happens in dmesg if there is a lot of write I/O while
suspending. (A number of parallel dd's with oflag=direct)

If I stop the I/O, the system eventually goes into suspend to RAM.
However, that takes a while, after the I/O has stopped, and also
from "Preparing system for suspend" log entry until it is actually
done.

Is this intentional?

It surely isn't.

Let me know how I can debug this further!
Ideally I'd like to be able to suspend the machine under I/O load,
too. (E.g. during a compile job.)

Can you reproduce this at your end, too?

Well, I didn't try suspending with a number of parallel dd's with oflag=direct
in the background, but otherwise I'm not reproducing the issue with
the patch applied.

Rafael