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

From: Jiri Slaby
Date: Mon Jan 31 2011 - 16:37:43 EST

On 01/20/2011 10:02 PM, Rafael J. Wysocki wrote:
> 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@xxxxxxxxxxxxxxxxxxxx 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.

It seems to suffice... No hangs still. Should I enable pm_async back
again to confirm the issue is still present?

Note that I also had had issues with fan which was at full speed after
resume sometimes (very rarely, like this issue). Full power-cycle was
needed to cure that. I don't see that now as well.

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