Bug#779412: /sys/power/pm_async defaulting to 1 : unreliable resume event execution

[Ritesh Raj Sarraf]

You should have reported that on the LMT bug.

AI to self: Check on when the resumption of userspace is granted.

@Ondrej: That's interesting. I get similar link reset on my SATA HDD, but I
never paid attention if the power savings settings were changed. Actually
so did powertop, which ideally should have detected it even if I did not.

On Tue, Apr 28, 2015 at 10:17 PM, Ondřej Grover <ondrej.grover at gmail.com>
wrote:

> Hi,
>
> I'd like to point out that my usage of echo 0 > ... pm_async in 780956 was
> related more to an apparent race issue in the HDD driver than a udev event.
> The udev trigger works correctly on my system, but with async pm often
> after it was triggered and applied requested settings on resume the HDD
> driver suddenly timed out and the SATA link was reset and lost the settings
> state.
>
> Kind regards,
> Ondřej Grover
>
>
> On Tue, Apr 28, 2015 at 6:00 PM, Chris <email.bug at arcor.de> wrote:
>
>>
>> There is now a specific spin-off from the closed
>> https://bugs.debian.org/780956 (laptop-mode-tools hooks not triggerd)
>> in the udev binary package: (reassing to src:systemd did not succeed)
>>
>>
>> To ensure packages have a reliable resume event hook available, udev may
>> echo 0 > /sys/power/pm_async, or some device blacklist may be needed (in
>> the kernel?) to disable async pm?.
>> https://bugs.debian.org/783638
>> (original reporters may subscribe)
>>
>> The relevant "trigger on resume" mechanism from udev seems to be:
>> ACTION=="add|remove", SUBSYSTEM=="machinecheck", RUN+="lmt-udev auto
>> force"
>>
>
>


-- 
Ritesh Raj Sarraf
RESEARCHUT - http://www.researchut.com
"Necessity is the mother of invention."
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