Re: Resume hangs [was: mmotm 2010-12-02-16-34 uploaded]

["Rafael J. Wysocki" <rjw@suse.com>]

On Thursday, January 20, 2011, Jiri Slaby wrote:
> On 01/06/2011 03:18 PM, Jiri Slaby wrote:
> > On 12/14/2010 11:22 PM, Rafael J. Wysocki wrote:
> >> On Tuesday, December 14, 2010, Jiri Slaby wrote:
> >>> On 12/13/2010 10:10 PM, Rafael J. Wysocki wrote:
> >>>> On Monday, December 13, 2010, Jiri Slaby wrote:
> >>>>> On 12/05/2010 02:08 PM, Rafael J. Wysocki wrote:
> >>>>>> On Sunday, December 05, 2010, Jiri Slaby wrote:
> >>>>>>> On 12/03/2010 01:34 AM, akpm@linux-foundation.org wrote:
> >>>>>>>> The mm-of-the-moment snapshot 2010-12-02-16-34 has been uploaded to
> >>>>>>>
> >>>>>>> Hi, this kernel regresses with respect to resume. It doesn't wake up,
> >>>>>>> the screen is black with blinking cursor at position [1, 1].
> >>>>>>> 2010-11-23-16-12 seemed to be OK. In this one it is 100% reproducible so
> >>>>>>> far.
> >>>>>>>
> >>>>>>> I'm using pm-suspend, any ideas what to test before I start to find the
> >>>>>>> reason on my own?
> >>>>>>
> >>>>>> Please try the pm_test tests for core, processors and devices, eg.:
> >>>>>
> >>>>> Hmm, I haven't seen the issues since then. So it had to be some kind of
> >>>>> coincidence -- I see the issue occasionally for some time already. Now
> >>>>> it triggered twice in a row after I updated the kernel.
> >>>>
> >>>> Hmm.  What hardware is that?
> >>>
> >>> What exactly do you want to know about it? It's some specific intel
> >>> desktop machine, 3 years old, 2 intel cores, 6G of mem, 2 sata disks in
> >>> raid, dvb-t usb receiver (af9015), usb keyboard and mouse.
> >>
> >> I'm seeing pretty much the same symptoms on quite different hardware, except
> >> for one thing: USB keyboard and mouse.
> >>
> >> Have you checked if writing 0 to /sys/power/pm_async helps?
> > 
> > It's very hard to reproduce (it happens once a week or two), so I can't
> > say yet. As it happened yesterday again, going to test it from now on.
> 
> Ok, I haven't seen the issue with 0 in /sys/power/pm_async for two weeks
> now (I added it to boot.local). I would say it's related to that...

In that case the next step would be to build the kernel with
CONFIG_PM_ADVANCED_DEBUG set and try to switch the async flag for individual
devices (it is located is /sys/devices/.../power/ for each device).

For example, I wonder if it is sufficient to unset it for all USB devices.

Thanks,
Rafael