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

From: Alan Stern
Date: Fri Feb 04 2011 - 15:07:29 EST


On Fri, 4 Feb 2011, Jiri Slaby wrote:

> On 02/04/2011 08:33 PM, Alan Stern wrote:
> > On Fri, 4 Feb 2011, Jiri Slaby wrote:
> >
> >>>> It seems to suffice... No hangs still. Should I enable pm_async back
> >>>> again to confirm the issue is still present?
> >>>
> >>> Yes, please, it would be good to know for sure.
> >>
> >> Ok, confirmed right now :).
> >>
> >> I disabled pm_async for USB again. What do you suggest next?
> >
> > What happens if you leave pm_async enabled but unplug all the USB
> > devices before suspending?
>
> Then I cannot suspend at all (ENOINPUTDEVICE)... And this would be
> painful as the bug occurs once a week or so.

You can suspend using a remote network login. Agreed, this would be
painful.

> > If there are any USB devices you can't
> > unplug, you can get an equivalent result by unconfiguring the root
> > hubs:
> >
> > for a in /sys/bus/usb/devices/usb* ; do
> > echo 0 >$a/bConfigurationValue
> > done
>
> Well, I can put this into suspend/resume scripts. What's the opposite
> operation? 1 > $a/bConfigurationValue?

Yes.

Alan Stern

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